Apparatuses, systems and methods for three-dimensional printing

ABSTRACT

The present disclosure provides three-dimensional (3D) objects, 3D printing processes, as well as methods, apparatuses and systems for the production of a 3D object. Methods, apparatuses and systems of the present disclosure may reduce or eliminate the need for auxiliary supports. The present disclosure provides three dimensional (3D) objects printed utilizing the printing processes, methods, apparatuses and systems described herein.

CROSS-REFERENCE

This application claim priority to U.S. Provisional Patent ApplicationSer. No. 62/015,230, filed Jun. 20, 2014, U.S. Provisional PatentApplication Ser. No. 62/028,760, filed Jul. 24, 2014, U.S. ProvisionalPatent Application Ser. No. 62/063,867, filed Oct. 14, 2014, U.S.Provisional Patent Application Ser. No. 62/136,378, filed Mar. 20, 2015,and U.S. Provisional Patent Application Ser. No. 62/168,699, filed May29, 2015, each of which is entirely incorporated herein by reference.

BACKGROUND

Three-dimensional (3D) printing (e.g., additive manufacturing) is aprocess for making a three-dimensional object of any shape from adesign. The design may be in the form of a data source such as anelectronic data source, or may be in the form of a hard copy. The hardcopy may be a two dimensional representation of a three dimensionalobject. The data source may be an electronic 3D model. 3D printing maybe accomplished through an additive process in which successive layersof material are laid down on top of each other. This process may becontrolled (e.g., computer controlled, manually controlled, or both). A3D printer can be an industrial robot.

3D printing can generate custom parts quickly and efficiently. A varietyof materials can be used in a 3D printing process including metal, metalalloy, ceramic or polymeric material. In an additive 3D printingprocess, a first material-layer is formed, and thereafter successivematerial-layers are added one by one, wherein each new material-layer isadded on a pre-formed material-layer, until the entire designedthree-dimensional structure (3D object) is materialized.

3D models may be created with a computer aided design package or via 3Dscanner. The manual modeling process of preparing geometric data for 3Dcomputer graphics may be similar to plastic arts, such as sculpting oranimating. 3D scanning is a process of analyzing and collecting digitaldata on the shape and appearance of a real object. Based on this data,three-dimensional models of the scanned object can be produced.

A large number of additive processes are currently available. They maydiffer in the manner layers are deposited to create the materializedstructure. They may vary in the material or materials that are used tomaterialize the designed structure. Some methods melt or soften materialto produce the layers. Examples for 3D printing methods includeselective laser melting (SLM), selective laser sintering (SLS), directmetal laser sintering (DMLS) or fused deposition modeling (FDM). Othermethods cure liquid materials using different technologies such asstereo lithography (SLA). In the method of laminated objectmanufacturing (LOM), thin layers (made inter alia of paper, polymer,metal) are cut to shape and joined together.

At times, the printed 3D object may bend, warp, roll, curl, or otherwisedeform during the 3D printing process. Auxiliary supports may beinserted to circumvent such bending, warping, rolling, curling or otherdeformation. These auxiliary supports may be removed from the printed 3Dobject to produce a desired 3D product (e.g., 3D object).

SUMMARY

In an aspect, a method for generating a three dimensional objectcomprises (a) providing (i) a first layer of powder material in anenclosure at a first time (t₁) and (ii) a second layer of powdermaterial in the enclosure at a second time (t₂) that follows t₁, whereinthe second layer of material is provided adjacent to the first layer ofpowder material; (b) transforming at least a portion of the powdermaterial in the second layer to form a transformed material, wherein thetransforming is with the aid of an energy beam having a first energy perunit area (S₁); and (c) removing energy from the second layer at a timeinterval from t₂ to a third time (t₃), wherein the thermal energy isremoved along a direction that is different from below the first layerof powder material, wherein during the time interval from t₂ to t₃, theenergy is removed at a second energy per unit area (S₂) that is at leastabout 0.3 times S₁, and wherein upon removal of the energy, thetransformed material solidifies to form at least a part of the threedimensional object.

The method can further comprise repeating operations (a) to (d). Theenergy beam can be an electromagnetic beam, charged particle beam, ornon-charged beam. The energy beam can be an electromagnetic beam,electron beam, or plasma beam. The energy that is removed can be thermalenergy. S₂ can be at least about 0.5 times S₁. S₂ can be at least about0.8 times S₁. In operation (b), a remainder of the first layer can be aportion of the powder material that was not transformed to form at leasta part of the three dimensional object. The remainder can be heated to amaximum temperature that is below a transforming temperature of thematerial.

The remainder of the first layer can be a portion of the powder materialthat was not transformed to form at least a part of the threedimensional object. The remainder can be supplied with energy at a thirdenergy per unit area S₃ that is less than or equal to about 0.1 timesS₁. The method may further comprise cooling the remainder atsubstantially the same rate as the rate of cooling the transformedmaterial. Operations (b) and (c) can be performed substantiallysimultaneously. Operation (b) can be performed using an electromagneticradiation beam. The electromagnetic radiation beam can be a laser light.Operation (c) can be performed using an electromagnetic radiation beam.The electromagnetic radiation beam can comprise infrared light. Inoperation (b) the portion of the layer of material can be transformed ata first temperature (T₁) without transforming the remainder. Theremainder can be heated to a second temperature (T₂) that is less thanabout T₁. The remainder can be devoid of a continuous layer extendingover about 1 millimeter or more. The remainder can be devoid of ascaffold enclosing at least part of the three-dimensional object. Theremainder can be devoid of a scaffold enclosing the three-dimensionalobject. The scaffold can comprise transformed material.

Adjacent can be above. The material can comprise elemental metal, metalalloy, ceramic or an allotrope of elemental carbon. The material cancomprise a powder material. Transforming can comprise fusing (e.g.,individual particles of the powder material). Fusing can comprisemelting, sintering or bonding (e.g., individual particles of the powdermaterial). Bonding can comprise chemically bonding. Chemically bondingcan comprise covalent bonding.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply powder materialfrom a powder dispensing member to a powder bed operatively coupled tothe powder dispensing member, wherein the supply of powder materialcomprises supply of (i) a first layer of powder material in an enclosureat a first time (t₁) and (ii) a second layer of powder material in theenclosure at a second time (t₂) that follows t₁, wherein the secondlayer of material is provided adjacent to the first layer of powdermaterial; (b) direct an energy beam from an energy source to the powderbed to transform at least a portion of the powder material to atransformed material that subsequently hardens to yield thethree-dimensional object, wherein the energy beam has a first energy perunit area (S₁); and (c) direct a cooling member to remove thermal energyfrom the second layer at a time interval from t₂ to a third time (t₃),wherein the thermal energy is removed along a direction that isdifferent from below the first layer of powder material, wherein duringthe time interval from t₂ to t₃, the energy is removed at a secondenergy per unit area (S₂) that is at least about 0.3 times S₁, andwherein upon removal of the energy, the transformed material solidifiesto form at least a part of the three dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing (i) a first layer of material in an enclosure ata first time (t₁) and (ii) a second layer of material in the enclosureat a second time (t₂) that follows t₁, wherein the second layer ofmaterial is provided adjacent to the first layer of material, whereinthe first layer of powder material and second layer of powder materialform a powder bed, and; transforming at least a portion of the materialin the second layer to form a transformed material; and (b) using acooling member adjacent to the first layer or the second layer to removethermal energy from the second layer at a time interval from t₂ to athird time (t₃), wherein the thermal energy is removed along a directionabove the powder bed, and wherein upon removal of thermal energy, thetransformed material solidifies to form at least a portion of thethree-dimensional object.

During the time interval from t₂ to t₃, an average temperature at apoint in the second layer can be maintained at less than or equal toabout 250° C. During the time interval from t₂ to t₃, the averagetemperature can be maintained at less than or equal to about 100° C.

Transforming can be with the aid of an energy beam having a first energyper unit area (S₁). In operation (c), during the time interval from t₂to t₃, thermal energy can be removed at a second energy per unit area(S₂) that can be at least about 0.3 times S₁. The second energy per unitarea (S₂) can be at least about 0.5 times S₁. The thermal energy can beremoved from a side of the first layer of powder material or the secondlayer of powder material. The thermal energy can be removed from a topsurface of the powder bed. The transforming operation may comprisefusing (e.g., individual particles of the powder material). The fusingcan comprise melting or sintering (e.g., the individual particles). Attime t₃, a third layer of powder material can be provided adjacent tothe second layer of powder material. The transforming can comprisedirecting an energy beam to at least a portion of the second layer.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accepts a first layer of powder material ata first time (t1) and a second layer of powder material at a second time(t2) that follows t1 to form a powder bed, wherein the second layer ofpowder material is adjacent to the first layer of powder material, andwherein the powder material comprises an elemental metal, metal alloy,ceramic, or an allotrope of elemental carbon; a cooling member adjacentto the first layer or the second layer, wherein the cooling memberremoves thermal energy from the second layer; and a controlleroperatively coupled to the cooling member and programmed to (i)transform at least a portion of the powder material in the second layerto form a transformed material, and (ii) use the cooling member toremove thermal energy from the second layer at a time interval from t2to a third time (t3), wherein the thermal energy is removed along adirection above the powder bed, and wherein upon removal of thermalenergy, the transformed material solidifies to form at least a portionof the three-dimensional object.

The cooling member can be disposed outside of the powder material (e.g.,not within the powder material). The system may further comprise anenergy source that provides an energy beam to at least a portion of thesecond layer. The controller can be operatively coupled to the energysource and programmed to direct the energy beam to at least the portionof the second layer. The controller can be programmed to (1) transformat least a portion of the powder material in the second layer to form atransformed material using an energy beam having a first energy per unitarea (S₁), and (2) use the cooling member to remove thermal energyduring the time interval from t₂ to t₃ at a second energy per unit area(S₂) that can be at least about 0.3 times S₁. The second energy per unitarea (S₂) can be at least about 0.5 times S₁. The controller can beprogrammed to use the cooling member to remove the thermal energy from aside of the first layer of material or the second layer of material,wherein the side can be different than the exposed surface of the secondlayer, or can be opposite to the exposed surface of the second layer.The controller can be programmed to use the cooling member to remove thethermal energy from a top surface of the powder bed.

The controller can be programmed to control an average temperature ofthe second layer of powder material. During the time interval from t₂ tot₃, the controller can be programmed to maintain an average temperatureat a point in the second layer at less than or equal to about 250° C.During the time interval from t₂ to t₃, the controller can be programmedto maintain the average temperature at less than or equal to about 100°C. The cooling member can be movable. The controller can be programmedto move the cooling member. The cooling member can be separated from thepowder bed by a gap. The gap can be at a spacing of less than or equalto about 50 millimeters. The gap can be at an adjustable spacing betweenthe cooling member and the powder bed. The controller can be programmedto regulate the adjustable spacing. The cooling member can comprise amaterial with a thermal conductivity of at least about 20 Watts permeter per degree Kelvin (W/mK). The cooling member may further comprisea cleaning member that removes the powder material or debris from asurface of the cooling member. The system may further comprise acollection member that collects a remainder of the powder material ordebris from the cooling member or the powder bed.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply powder materialfrom a powder dispensing member to a powder bed operatively coupled tothe powder dispensing member, wherein the supply of powder materialcomprises supply of (i) a first layer of powder material in an enclosureat a first time (t₁) and (ii) a second layer of powder material in theenclosure at a second time (t₂) that follows t₁, wherein the secondlayer of material is provided adjacent to the first layer of powdermaterial; (b) direct an energy beam from an energy source to the powderbed to transform at least a portion of the powder material to atransformed material that subsequently hardens to yield thethree-dimensional object; and (c) direct a cooling member adjacent tothe first layer or the second layer to remove thermal energy from thesecond layer at a time interval from t₂ to a third time (t₃), whereinthe thermal energy is removed along a direction above the powder bed,and wherein upon removal of thermal energy, the transformed materialsolidifies to form at least a portion of the three-dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing (i) a first layer of material in an enclosure ata first time (t₁) and (ii) a second layer of material in the enclosureat a second time (t₂) that follows t₁, wherein the second layer ofmaterial is provided adjacent to the first layer of material; (b)transforming at least a portion of the material in the second layer toform a transformed material; and (c) removing thermal energy from thesecond layer at a time interval from t₂ to a third time (t₃), whereinduring a time interval from t₁ to t₂, an average temperature at anypoint in the second layer is maintained within at most about 250 degreesCelsius, and wherein removing the energy results in hardening thetransformed material to form at least a portion of the three dimensionalobject.

A third layer of material can be provided at times t₃. The averagetemperature at any point in the second layer can be maintained within atmost about 100 degrees Celsius. The average temperature at any point inthe second layer can be maintained within at most about 10 degreesCelsius range. The method may further comprise fusing a portion of thefirst layer prior to providing the second layer. Fusing may comprisemelting or sintering. The method may further comprise cooling theportion prior to operation (b).

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply powder materialfrom a powder dispensing member to a powder bed operatively coupled tothe powder dispensing member, wherein the supply of powder materialcomprises supply of (i) a first layer of material in an enclosure at afirst time (t₁) and (ii) a second layer of material in the enclosure ata second time (t₂) that follows t₁, wherein the second layer of materialis provided adjacent to the first layer of material; (b) direct anenergy beam from an energy source to the powder bed to transform atleast a portion of the powder material to a transformed material thatsubsequently hardens to yield the three-dimensional object; and (c)direct a cooling member adjacent to the first layer or the second layerto remove thermal energy from the second layer at a time interval fromt₂ to a third time (t₃), wherein during a time interval from t₁ to t₂,an average temperature at any point in the second layer is maintainedwithin at most about 250 degrees Celsius, and wherein removing theenergy results in hardening the transformed material to form at least aportion of the three dimensional object.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accepts a first layer of material at a firsttime (t₁) and a second layer of material at a second time (t₂) thatfollows t₁, wherein the second layer of material is adjacent to thefirst layer of powder material; a cooling member adjacent to the firstlayer or the second layer, wherein the cooling member removes thermalenergy from the second layer; and a controller operatively coupled tothe cooling member and programmed to (i) transform at least a portion ofthe material in the second layer to form a transformed material, and(ii) using the cooling member to remove thermal energy from the secondlayer at a time interval from t₂ to a third time (t₃), wherein during atime interval from t₁ to t₂, an average temperature at any point in thesecond layer is maintained within at most about 250 degrees Celsius, andwherein upon removal of thermal energy, the transformed materialsolidifies to form at least a part of the three-dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing (i) a first layer of material in an enclosure ata first time (t₁) and (ii) a second layer of material in the enclosureat a second time (t₂) that follows t₁, wherein the second layer ofmaterial is provided adjacent to the first layer of material; (b)transforming at least a portion of the material in the second layer toform a transformed material; and (c) removing thermal energy from thesecond layer at a time interval from t₂ to a third time (t₃), wherein amaximum temperature of the transformed material is at least about 400°C. or more, and wherein a remainder of the powder material that did nottransform to subsequently form a hardened material that is at least aportion of the three dimensional object, does not exceed a temperatureof about 300° C., and wherein removing the energy results in hardeningthe transformed material to form at least a portion of the threedimensional object.

The hardened material can be devoid of auxiliary supports. The remaindermay not exceed a temperature of about 200° C. The remainder may notexceed a temperature of about 150° C. The method can further compriserepeating operations (a) to (c). Operations (a)-(c) can be performed ata pressure that can be about 10⁻⁶ Torr or more. The method may furthercomprise removing the hardened material from the remainder of powdermaterial that did not fuse to form at least a portion of the threedimensional object. The method may further comprise cooling the portionand the remainder of powder material that did not fuse to form at leasta part of the three dimensional object. The portion and the remaindercan be cooled at substantially the same rate. The second temperature canbe at most about 350° C. or less. The method may further compriseseparating the remainder of powder material that did not fuse to form atleast a part of the three dimensional object, from the at least aportion of the three dimensional object.

The material can comprise powder material. The material can compriseelemental metal, metal alloy, ceramics, or an allotrope of elementalcarbon. Transforming can comprise fusing. Fusing can comprise melting orsintering. The hardened material can comprise solidified material.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to (a) supply powder materialfrom a powder dispensing member to a powder bed operatively coupled tothe powder dispensing member, wherein the supply of powder materialcomprises supply of (i) a first layer of material in an enclosure at afirst time (t₁) and (ii) a second layer of material in the enclosure ata second time (t₂) that follows t₁, wherein the second layer of materialis provided adjacent to the first layer of material; (b) direct anenergy beam from an energy source to the powder bed to transform atleast a portion of the powder material to a transformed material thatsubsequently hardens to yield the three-dimensional object; and (c)direct a cooling member adjacent to the first layer or the second layerto remove thermal energy from the second layer at a time interval fromt₂ to a third time (t₃), wherein a maximum temperature of thetransformed material is at least about 400° C. or more, and wherein aremainder of the powder material that did not transform to subsequentlyform a hardened material that is at least a portion of the threedimensional object, does not exceed a temperature of about 300° C., andwherein removing the energy results in hardening the transformedmaterial to form at least a portion of the three dimensional object.

In another aspect, a system for generating a three-dimensional objectcomprises: an enclosure that accepts a first layer of material at afirst time (t₁) and a second layer of material at a second time (t₂)that follows t₁, wherein the second layer of material is adjacent to thefirst layer of powder material; a cooling member adjacent to the firstlayer or the second layer, wherein the cooling member removes thermalenergy from the second layer; and a controller operatively coupled tothe cooling member and programmed to (i) transform at least a portion ofthe material in the second layer to form a transformed material, and(ii) using the cooling member to remove thermal energy from the secondlayer at a time interval from t₂ to a third time (t₃), wherein a maximumtemperature of the transformed material is at least about 400° C. ormore, and wherein a remainder of the powder material that did nottransform to subsequently form a hardened material that is at least apart of the three dimensional object, does not exceed a temperature ofabout 300° C., and wherein upon removal of thermal energy, thetransformed material solidifies to form at least a part of thethree-dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing a layer of material in an enclosure having anaverage temperature (T₀); (b) transforming at least a portion of thematerial in the second layer to form a transformed material, wherein theportion reaches a maximum temperature (T₂), that is greater than T₀; and(c) removing thermal energy from the layer to reach an averagetemperature T₁ in a time period that is at most about 240 seconds, toform the transformed material a hardened material that is at least apart of the three dimensional object, wherein T₁ is greater or equal toT₀ and lower than T_(z), wherein T₁ is not greater than T₀ by more thanabout 0.8 times (T₂−T₀).

The method may further comprise repeating operations (a) to (c), whereina subsequent layer of powder material is provided on a previouslyprovided layer of powder material. A first provided layer of powdermaterial can be provided on a base. The time period can be at most about120 seconds. The time period can be at most about 60 seconds. The timeperiod can be at most about 30 seconds. T₁ can be not greater than T₀ bymore than about 0.5 times (T₂−T₀). T₁ can be not greater than T₀ by morethan about 0.3 times (T₂−T₀). T₁ can be not greater than T₀ by more thanabout 0.1 times (T₂−T₀).

Hardening can comprise solidifying. Transforming can comprise fusing.Fusing can comprise melting or sintering. The energy can comprise anenergy beam. The energy beam can comprise an electromagnetic beam,electron beam, or a plasma beam. The electromagnetic beam can comprise alaser beam or a microwave beam.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material having an average temperature (T₀) from a powderdispensing member to a powder bed operatively coupled to the powderdispensing member; (b) direct an energy beam from an energy source tothe powder bed to transform at least a portion of the powder material toa transformed material that subsequently hardens to yield thethree-dimensional object, wherein the portion reaches a maximumtemperature (T₂), that is greater than T₀; and (c) direct a coolingmember adjacent to the layer to remove thermal energy from the layer toreach an average temperature T₁ in a time period that is at most about240 seconds, to form from the transformed material a hardened materialthat is at least a part of the three dimensional object, wherein T₁ isgreater or equal to T₀ and lower than T₂, wherein T₁ is not greater thanT₀ by more than about 0.8 times (T₂−T₀).

In another aspect, a system for generating a three-dimensional objectcomprises: an enclosure that accepts a layer of material having anaverage base temperature (T₀); a cooling member adjacent to the layer,wherein the cooling member removes thermal energy from the layer; and acontroller operatively coupled to the cooling member and programmed to(i) transform at least a portion of the material in the layer to form atransformed material, wherein the transformed material reaches a maximumtemperature (T₂) and (ii) using the cooling member to remove thermalenergy such that after 240 seconds or less, the transformed materialforms hardened material that is at least a part of the three dimensionalobject, wherein T₁ is greater or equal to T₀ and lower than T₂, whereinT₁ is not greater than T₀ by more than about 0.8 times (T₂−T₀).

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises elemental metal, metal alloy, ceramic or an allotropeof elemental carbon; (b) direct an energy beam from an energy source tothe powder bed to transform at least a portion of the powder material toa transformed material that subsequently hardens to yield thethree-dimensional object; and (c) direct a cooling member to removeenergy from the powder bed, wherein the cooling member facilitatesremoval of at least 30 percent of the energy in the direction above anexposed surface of the powder bed.

In another aspect, a method for generating a three-dimensional objectcomprises (a) providing a material bed in an enclosure; (b) directing anenergy beam at the material along a path to transform at least a portionof the material to form a transformed material, which transformedmaterial hardens to form a hardened material as part of thethree-dimensional object; and (c) bringing a heat sink adjacent to anexposed surface of the material bed to remove thermal energy from thematerial bed, wherein during the removal of thermal energy from thematerial bed, the heat sink is separated from the exposed surface by agap, and wherein the exposed surface of the material bed is a topsurface of the powder bed.

The gap can be at a spacing between the heat sink and the top surfacethat is less than or equal to about 50 millimeters. The path can begenerated according to a model of the three-dimensional object. Thetransforming can comprise fusing individual particles of the powdermaterial. Fusing can comprise sintering, melting or binding theindividual particles.

In another aspect, an apparatus for forming a three-dimensional object,comprises a controller that is programmed to: (a) supply a layer ofmaterial from a material dispensing member to a material bed operativelycoupled to the material dispensing member; (b) direct an energy beamfrom an energy source to the material bed to transform at least aportion of the powder material to a transformed material thatsubsequently hardens to yield the three-dimensional object; and (c)direct a cooling member to remove energy from the material bed, whereinthe cooling member is disposed adjacent to an exposed surface of thematerial bed, wherein during the removal of thermal energy from thematerial bed, the heat sink is separated from the exposed surface by agap, and wherein the exposed surface of the material bed is a topsurface of the powder bed.

In another aspect, a system for generating a three-dimensional objectcomprises: an enclosure that accommodates a material bed; an energysource that provides an energy beam to the material in the material bed;a heat sink that removes thermal energy from the powder bed, whereinduring removal of thermal energy from the material bed, the heat sink isseparated from an exposed surface of the material bed by a gap, andwherein the exposed surface of the powder bed is a top surface of thepowder bed; and a controller operatively coupled to the energy sourceand the heat sink and programmed to (i) direct the energy beam at thematerial along a path to transform at least a portion of the material toform a transformed material, which transformed material hardens to forma hardened material as at least a part of the three-dimensional object,and (ii) bring the heat sink adjacent to the exposed surface of thepowder bed to remove thermal energy from the powder bed.

The energy beam can comprise an electromagnetic beam, a charged particlebeam or a non-charged particle beam. The energy beam can comprise alaser beam.

The heat sink can be disposed within a path of the energy beam thatextends from the energy source to the powder material. The heat sink cancomprise at least one opening, and during use, the energy beam can bedirected from the energy source to the powder material through the atleast one opening. The heat sink can be movable. The controller can beprogrammed to move the heat sink. The enclosure can be a vacuum chamber.The enclosure has a pressure of at least about 10⁻⁶ Torr. The heat sinkcan be thermally coupled to the powder material trough the gap. The gapcan comprise a gas. The gap can be at a spacing between the heat sinkand the exposed surface that is less than or equal to about 50millimeters. The gap can be at an adjustable spacing between the heatsink and the exposed surface. The controller can be programmed toregulate the spacing. The controller can be programmed to regulate thespacing by using an energy per unit area that is sufficient to transformthe at least a portion of the material. The controller can be programmedto regulate at least one of the spacing and the energy source to providean energy per unit area that is sufficient to form the three-dimensionalobject at a deviation from a model of the three-dimensional object thatis less than or equal to about the sum of 25 micrometers and onethousandths of the fundamental length scale of the three-dimensionalobject. The heat sink can facilitate the transfer of thermal energy fromthe powder material via convective heat transfer. The heat sink cancomprise a material with a thermal conductivity of at least about 20Watts per meter per degree Kelvin (W/mK). The heat sink can furthercomprise a cleaning member that removes the powder material or debrisfrom a surface of the heat sink. The cleaning member can comprise arotating brush. The cleaning mechanism can comprise a rotating brushthat rotates when the heat sinks moves. The heat sink can comprise atleast one surface that can be coated with an anti-stick layer thatreduces or prevents absorption of the powder material or debris on theat least one surface. The system may further comprise a collectionmember that collects a remainder of the powder material or debris fromthe heat sink or the powder bed. The mechanism for collection of atleast one of remaining powder and debris can comprise a venturiscavenging nozzle. The venturi scavenging nozzle can be aligned with theenergy source such that an energy beam from the energy source passesthrough an opening of the venturi scavenging nozzle. The mechanism forcollection of at least one of remaining powder and debris can compriseone or more vacuum suction port. The mechanism for collection of atleast one of remaining powder and debris can be coupled to the heatsink. The collection member can comprise one or more sources of negativepressure. The collection member can be operatively coupled to the heatsink. The system may further comprise a source of the material thatsupplies the material to the enclosure. The heat sink may facilitate theremoval of energy without substantially changing the position of the atleast part of the three dimensional object. The heat sink can be inproximity to at least the layer. The heat sink can be located betweenthe energy source and the layer. The heat sink can be movable to or froma position that can be between the energy source and the base. The heatsink can comprise at least one opening though which energy from theenergy source can be directed to the portion of the layer. The systemmay further comprise an additional energy source that provides energy toa remainder of the layer that did not transform to subsequently form atleast a portion of the three dimensional object. The energy source cansupply energy at an energy per unit area S1 and the additional energysource can supply energy at a second energy per unit area S2, wherein S2can be less than S1. S2 can be less than or equal to about 0.5 times S1.S2 can be less than or equal to about 0.2 times S1. S2 can be less thanor equal to about 0.1 times S1. The system may further comprise achamber containing the base. The chamber can be a vacuum chamber. Thechamber can be at a pressure that is greater than about 10⁻⁶ Torr. Thechamber may provide an inert gaseous environment. The gap can comprise agas. The gap can be at an adjustable distance between the layer and theheat sink. The heat sink can be integrated with a leveling mechanismthat provides and/or moves the material adjacent to the base or to apreviously deposited layer of material. The heat sink can be integratedwith a removing mechanism that removes and/or recycles the materialadjacent to the base or to a previously deposited layer of powdermaterial. The heat sink may facilitate the transfer of energy from thelayer via convective heat transfer.

Transform can comprise fuse. Fuse can comprise melt, sinter or bind.Bind can comprise chemically bind. Chemically bind can comprisecovalently bind. The energy source provides energy by an electromagneticbeam, laser beam, electron beam, plasma beam, or microwave beam.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the material dispensing member; (b) direct anenergy beam from an energy source to the powder bed to transform atleast a portion of the powder material to a transformed material thatsubsequently hardens to yield the three-dimensional object that issuspended in the powder bed; and (c) direct a leveling member to levelan exposed surface of the material bed such that the three-dimensionalobject suspended in the material bed is displaced by about 300micrometers or less.

In another aspect, a method for generating a three-dimensional objectsuspended in a material bed, comprises (a) dispensing a material into anenclosure to provide the material bed; (b) generating thethree-dimensional object from a portion of the material, wherein upongeneration the three-dimensional object is suspended in the materialbed; and (c) using a leveling member to level an exposed surface of thematerial bed such that the three-dimensional object suspended in thematerial bed is displaced by about 300 micrometers or less.

Generating can comprise additively generating. The material bed can bedevoid of a supporting scaffold substantially enclosing thethree-dimensional object. In operation (c), the three-dimensional objectcan be displaced by about 20 micrometers or less. The material maycomprise a powder material. The material may comprise elemental metal,metal alloy, ceramic, or an allotrope of elemental carbon. The powdermaterial can be devoid of at least two metals that are present at aratio that forms a eutectic alloy. The powder material can comprise atmost a metal that can be substantially of a single elemental metalcomposition. The powder material can comprise a metal alloy that can beof a single metal alloy composition. The three-dimensional object can beplanar. The three-dimensional object can be a wire. Thethree-dimensional object can be devoid of auxiliary support features.The three-dimensional object can comprise auxiliary support featuresthat are suspended in the powder bed.

In another aspect, a system for generating a three-dimensional objectsuspended in a material bed comprises: an enclosure that accommodatesthe powder bed; an energy source that provides an energy beam to thematerial in the material bed; a leveling member that levels an exposedsurface of the material bed; and a controller operatively coupled to theenergy source and the leveling member and programmed to (i) receiveinstructions to generate the three-dimensional object, (ii) generate thethree-dimensional object from a portion of the material in accordancewith the instructions, wherein upon generation the three-dimensionalobject is suspended in the material bed, and (iii) direct the levelingmember to level the exposed surface of the material bed such that thethree-dimensional object suspended in the material bed is displaced byabout 300 micrometers or less.

Upon generation of the three-dimensional object, the material bed can bedevoid of a supporting scaffold substantially enclosing thethree-dimensional object. The material can comprise elemental metal,metal alloy, ceramic, or an allotrope of elemental carbon. The materialcan comprise a powder material. The system may further comprise a powderdispenser that provides the powder material into the enclosure. Theleveling mechanism can be coupled to the powder dispenser. The powderdispenser can be disposed adjacent to the powder bed. The powderdispenser may comprise an exit opening that can be located at adifferent location than a bottom portion of the powder dispenser thatfaces the powder bed. The exit opening can be located at a side of thepowder dispenser. The side can be a portion of the powder dispenser thatdoes not face the powder bed or does not face a direction opposite tothe powder bed. The exit opening can comprise a mesh. The controller canbe operatively coupled to the powder dispenser and programmed to controlan amount of the material that can be dispensed by the powder dispenserinto the enclosure. The controller can be operatively coupled to thepowder dispenser and programmed to control a position of the powderdispenser. The powder dispenser can be movable. The system may furthercomprise one or more mechanical members operatively coupled to thepowder dispenser, wherein the one or more mechanical members subject thepowder dispenser to vibration. The controller can be operatively coupledto the one or more mechanical members. The controller can be programmedto control the one or more mechanical members to regulate an amount ofthe powder material that is dispensed by the powder dispenser into theenclosure. The controller can be programmed to control a position of theleveling member, wherein the leveling member can be movable. Thecontroller can be programmed to control a force or pressure exerted bythe leveling member on the powder material. The system may furthercomprise a removal unit that removes excess material from the materialbed. The removal unit can comprise a source of vacuum, magnetic force,electric force, or electrostatic force. The removal unit can comprise areservoir for accommodating an excess of powder material. The removalunit can comprise one or more sources of negative pressure incommunication (e.g., fluid communication) with the powder bed, which oneor more sources of negative pressure are for removing an excess ofpowder material from the powder bed. The controller can be programmed todirect removal of an excess of powder material using the removal unit.The leveling member can comprise a knife. The system may furthercomprise a cooling member. The cooling member may be in proximity to thelayer. The cooling member can be located between the energy source andthe layer. The three dimensional object can be devoid of auxiliarysupports. The cooling member can be movable to or from a position thatcan be between the energy source and the powder material. The coolingmember may facilitate the cooling of the fused portion of the layerand/or facilitates the cooling of a remainder of the layer that did nottransform to subsequently form at least a portion of the threedimensional object. The cooling member may facilitate the cooling of theportion and the remainder at substantially the same rate. The coolingmember can be separated from the layer and/or from the base by a gap.The gap can comprise a gas. The gap has a cross-section that can be atmost about 1 millimeter or less. The gap can be adjustable. Thecontroller can be operatively coupled to the cooling member and can beable to adjust the gap distance from the material bed. The coolingmember can be adapted to be positioned between the base and the energysource. The cooling member may track an energy that can be applied tothe portion of the layer by the energy source. The controller can beoperatively coupled to the cooling member and regulates the tracking ofthe cooling member. The cooling member can comprise at least one openingthough which energy from the energy source can be directed to theportion of the layer. The cooling member can be substantiallytransparent. The cooling member can comprise one or more heat sinks. Theenergy source may direct energy to the portion of the layer throughradiative heat transfer. The energy source can be a laser. The systemmay further comprise an additional energy source that provides energy toa remainder of the layer that did not fuse to subsequently form at leasta part of the three dimensional object. The additional energy source canbe a laser or an infrared (IR) radiation source. The energy source mayprovide energy via an electromagnetic beam, laser beam, electron beam,plasma beam, or microwave beam. The system may further comprise achamber comprising a base above which the material bed can be disposed.The chamber can be a vacuum chamber. The chamber may provide an inertgaseous environment. The system may further comprise an optical systemthat direct energy from the energy source to a predetermined position ofthe layer. The optical system can comprise a mirror (e.g., deflectionmirror or galvanometer mirror), a lens, a fiber, a beam guide, arotating polygon or a prism. The controller can control the deflectionand/or the modulation of the energy beam (e.g., electromagnetic beam).The controller can control the optical path (e.g., vector) traveled bythe energy beam (e.g., by controlling the optical system). Thecontroller can be programmed to control a trajectory of the energysource with the aid of the optical system. The processor can be incommunication with a central processing unit that supplies instructionsto the controller to generate the three dimensional object. Thecommunication can be network communication. The central processing unitcan be a remote computer. The remote computer system may provideinstructions pertaining to a three dimensional model to the controller,and wherein the controller directs the energy source to supply energybased on the instructions pertaining to the three dimensional model. Thedesign instructions may be provided using a file having a StandardTessellation Language file format. The controller can be programmed tooptimize at least the amount, intensity or duration of energy suppliedby the energy source. The controller can be programmed to optimize atrajectory or a path of energy supplied from the energy source to the atleast a portion of the layer. The controller can be programmed tooptimize the removal of energy from the at least a portion of the layer.The controller can be programmed to control a temperature profile of thebase that can be separate from a temperature profile of the layer. Thecontroller can be programmed to regulate the transformation of theportion of the layer without transforming a remainder of the layer.

In another aspect, an apparatus for generating a three-dimensionalobject comprises: an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,(ii) has an exposed layer surface with a surface area of about onecentimeter squared (cm²) or more, and (iii) is devoid of an auxiliarysupport feature or auxiliary support feature mark that is indicative ofa presence or removal of the auxiliary support feature, and wherein agiven layer of the layered structure is devoid of at least two metalsthat form a eutectic alloy.

In another aspect, an apparatus for forming a three-dimensional object,comprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises elemental metal, metal alloy, ceramic or an allotropeof elemental carbon; and (b) direct an energy beam from an energy sourceto the powder bed to transform at least a portion of the powder materialto a transformed material that subsequently hardens to yield thethree-dimensional object that (i) is devoid of surface featuresindicative of layer removal during or after the three-dimensionalprinting process, (ii) has an exposed layer surface with a surface areaof about one centimeter squared (cm²) or more, and (iii) is devoid of anauxiliary support feature or auxiliary support feature mark that isindicative of a presence or removal of the auxiliary support feature,and wherein a given layer of the layered structure is devoid of at leasttwo metals that form a eutectic alloy.

In another aspect, an apparatus for generating a three-dimensionalobject, comprising: an enclosure that accommodates a powder bedcomprising the powder material comprising an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; and an energysource that provides an energy beam to the powder material in the powderbed to form at least a portion of a three-dimensional object, whereinupon formation the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of about one centimeter squared (cm²) or more, and(iii) is devoid of an auxiliary support feature or auxiliary supportfeature mark that is indicative of a presence or removal of theauxiliary support feature, and wherein a given layer of the layeredstructure is devoid of at least two metals that form a eutectic alloy.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of about one centimeter squared (cm²) or more, and(iii) is devoid of an auxiliary support feature or auxiliary supportfeature mark that is indicative of a presence or removal of theauxiliary support feature, and wherein a given layer of the layeredstructure is devoid of at least two metals that form a eutectic alloy.

The surface area can be about two centimeter squared (cm²) or more.

The auxiliary support feature can comprise a linear structure. Theauxiliary support feature can comprise a non-linear structure. Theauxiliary support feature can comprise a ledge, column, fin, pin, blade,or scaffold. The auxiliary support feature can comprise a sinteredpowder scaffold. The sintered powder scaffold can be formed of thematerial. The auxiliary support feature mark can comprise a mark of amold embedded on the three-dimensional object. The auxiliary supportfeature mark can comprise a geometric deformation of one or more of thesuccessive solidified melt pools, which deformation can be complementaryto the auxiliary support feature. A given layer of the layered structurecan comprise a plurality of solidified material melt pools.

The three-dimensional object can be devoid of surface features that areindicative of the use of a trimming process during or after theformation of the three-dimensional object. The trimming process may bean operation conducted after the completion of the 3D printing process.The trimming process may be a separate operation from the 3D printingprocess. The trimming may comprise cutting (e.g., using a piercing saw).The trimming can comprise polishing or blasting. The blasting cancomprise solid blasting, gas blasting or liquid blasting. The solidblasting can comprise sand blasting. The gas blasting can comprise airblasting. The liquid blasting can comprise water blasting. The blastingcan comprise mechanical blasting. The layered structure can be asubstantially repetitive layered structure. Each layer of the layeredstructure has an average layer thickness greater than or equal to about5 micrometers (μm). Each layer of the layered structure has an averagelayer thickness less than or equal to about 1000 micrometers (μm). Thelayered structure can comprise individual layers of the successivesolidified melt pools. A given one of the successive solidified meltpools can comprise a substantially repetitive material variationselected from the group consisting of variation in grain orientation,variation in material density, variation in the degree of compoundsegregation to grain boundaries, variation in the degree of elementsegregation to grain boundaries, variation in material phase, variationin metallurgical phase, variation in material porosity, variation incrystal phase, and variation in crystal structure. A given one of thesuccessive solidified melt pools can comprise a crystal. The crystal cancomprise a single crystal. The layered structure can comprise one ormore features indicative of solidification of melt pools during thethree-dimensional printing process. The layered structure can comprise afeature indicative of the use of the three-dimensional printing process.The three-dimensional printing process can comprise selective lasermelting (SLM), selective laser sintering (SLS), direct metal lasersintering (DMLS), or fused deposition modeling (FDM). Thethree-dimensional printing process can comprise selective laser melting.A fundamental length scale of the three-dimensional object can be atleast about 120 micrometers.

The allotrope of elemental carbon can be selected from the groupconsisting of amorphous carbon, graphite, graphene, fullerene, anddiamond. The fullerene can be selected from the group consisting ofspherical, elliptical, linear, and tubular. The fullerene can beselected from the group consisting of buckyball and carbon nanotube. Thematerial can comprise a reinforcing fiber. The reinforcing fiber cancomprise carbon fiber, Kevlar®, Twaron®, ultra-high-molecular-weightpolyethylene, or glass fiber.

In another aspect, an apparatus for generating a three-dimensionalobject, comprising: an enclosure that accommodates a powder bedcomprising the powder material comprising an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; and an energysource that provides an energy beam to the powder material in the powderbed to form at least a portion of a three-dimensional object, whereinupon formation the three-dimensional object (i) is devoid of anauxiliary support feature or auxiliary support feature mark that isindicative of a presence or removal of the auxiliary support feature,(ii) is devoid of surface features indicative of layer removal during orafter the three-dimensional printing process, and (iii) has an exposedlayer surface with a surface area of at least about one centimetersquared (cm²), and wherein each layer of the layered structure of thethree-dimensional object comprises at most substantially a singleelemental metal composition.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises elemental metal, metal alloy, ceramic or an allotropeof elemental carbon; and (b) direct an energy beam from an energy sourceto the powder bed to transform at least a portion of the powder materialto a transformed material that subsequently hardens to yield thethree-dimensional object that (i) is devoid of an auxiliary supportfeature or auxiliary support feature mark that is indicative of apresence or removal of the auxiliary support feature, (ii) is devoid ofsurface features indicative of layer removal during or after thethree-dimensional printing process, and (iii) has an exposed layersurface with a surface area of at least about one centimeter squared(cm²), and wherein each layer of the layered structure of thethree-dimensional object comprises at most substantially a singleelemental metal composition.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises: a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of anauxiliary support feature or auxiliary support feature mark that isindicative of a presence or removal of the auxiliary support feature,(ii) is devoid of surface features indicative of layer removal during orafter the three-dimensional printing process, and (iii) has an exposedlayer surface with a surface area of at least about one centimetersquared (cm²), and wherein each layer of the layered structure of thethree-dimensional object comprises at most substantially a singleelemental metal composition.

The surface area can be at least about two centimeter squared (cm²).Each layer of the three-dimensional object can comprise at most a singlemetal alloy composition at a deviation of about 2% or less from a singlemetal alloy composition. Each layer of the three-dimensional object cancomprise at most substantially a single metal alloy composition.Substantially can comprise a composition deviation of about 2% or lessfrom a single metal alloy composition.

In another aspect, an apparatus for generating a three-dimensionalobject comprises: an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,(ii) has an exposed layer surface with a surface area of at least aboutone centimeter squared (cm²), and (iii) is devoid of an auxiliarysupport feature or auxiliary support feature mark that is indicative ofa presence or removal of the auxiliary support feature, and wherein agiven layer of the layered structure has a radius of curvature of atleast about 50 centimeters as measured by optical microscopy.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises elemental metal, metal alloy, ceramic or an allotropeof elemental carbon; and (b) direct an energy beam from an energy sourceto the powder bed to transform at least a portion of the powder materialto a transformed material that subsequently hardens to yield thethree-dimensional object that (i) is devoid of surface featuresindicative of layer removal during or after the three-dimensionalprinting process, (ii) has an exposed layer surface with a surface areaof at least about one centimeter squared (cm²), and (iii) is devoid ofan auxiliary support feature or auxiliary support feature mark that isindicative of a presence or removal of the auxiliary support feature,and wherein a given layer of the layered structure has a radius ofcurvature of at least about 50 centimeters as measured by opticalmicroscopy.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises: a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of at least about one centimeter squared (cm²), and(iii) is devoid of an auxiliary support feature or auxiliary supportfeature mark that is indicative of a presence or removal of theauxiliary support feature, wherein a given layer of the layeredstructure has a radius of curvature of at least about 50 centimeters asmeasured by optical microscopy.

The given layer can be a first-generated layer. The radius of curvaturecan be at least about 100 centimeters (cm) as measured by opticalmicroscopy. A plurality of layers of the layered structure have theradius of curvature of at least about 50 centimeters (cm) as measured byoptical microscopy.

In another aspect, an apparatus for generating a three-dimensionalobject comprises: an enclosure that accommodates a powder bed comprisingthe powder material comprising a ceramic, or an allotrope of elementalcarbon; and an energy source that provides an energy beam to the powdermaterial in the powder bed to form at least a portion of athree-dimensional object, wherein upon formation the three-dimensionalobject (i) is devoid of surface features indicative of layer removalduring or after the three-dimensional printing process, and (ii) isdevoid of one or more auxiliary support features or auxiliary supportfeature marks that are indicative of a presence or removal of theauxiliary support feature.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises ceramic or an allotrope of elemental carbon; and (b)direct an energy beam from an energy source to the powder bed totransform at least a portion of the powder material to a transformedmaterial that subsequently hardens to yield the three-dimensional objectthat (i) is devoid of surface features indicative of layer removalduring or after the three-dimensional printing process, and (ii) isdevoid of one or more auxiliary support features or auxiliary supportfeature marks that are indicative of a presence or removal of theauxiliary support feature.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises a layered structurecomprising successive solidified melt pools of a material that comprisesa ceramic or an allotrope of elemental carbon, wherein thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,and (ii) is devoid of one or more auxiliary support features orauxiliary support feature marks that are indicative of a presence orremoval of the auxiliary support feature.

In another aspect, an apparatus for generating a three-dimensionalobject comprises: an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,and (ii) comprises two auxiliary support features or auxiliary supportfeature marks that is indicative of a presence or removal of theauxiliary support features; wherein the layered structure has a layeringplane, wherein the two auxiliary support features or support marks arespaced apart by at least about 40.5 millimeters or more, and wherein theacute angle between the straight line connecting the two auxiliarysupport features or support marks and the direction of normal to thelayering plane is from about 45 degrees to about 90 degrees.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; and (b) direct an energy beam from anenergy source to the powder bed to transform at least a portion of thepowder material to a transformed material that subsequently hardens toyield the three-dimensional object that (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, and (ii) comprises two auxiliarysupport features or auxiliary support feature marks that are indicativeof a presence or removal of the auxiliary support features, wherein thelayered structure has a layering plane, wherein the two auxiliarysupport features or support marks are spaced apart by at least about40.5 millimeters or more; and wherein the acute angle between thestraight line connecting the two auxiliary support features or supportmarks and the direction of normal to the layering plane is from about 45degrees to about 90 degrees.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises: a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, and (ii) comprises two auxiliarysupport features or auxiliary support feature marks that are indicativeof a presence or removal of the auxiliary support features, wherein thelayered structure has a layering plane, wherein the two auxiliarysupport features or support marks are spaced apart by at least about40.5 millimeters or more, and wherein the acute angle between thestraight line connecting the two auxiliary support features or supportmarks and the direction of normal to the layering plane is from about 45degrees to about 90 degrees. Any two auxiliary support features orauxiliary support marks may be spaced apart by at least about 45millimeters or more.

In another aspect, an apparatus for generating a three-dimensionalobject comprises an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,and (ii) comprises an auxiliary support feature or auxiliary supportfeature mark that is indicative of a presence or removal of theauxiliary support feature, wherein the layered structure has a layeringplane, wherein X is a point residing on the surface of the threedimensional object and Y is the closest auxiliary support feature orauxiliary support feature mark to X, wherein Y is spaced apart from X byat least about 10.5 millimeters or more; wherein the sphere of radius XYis devoid of auxiliary support feature or auxiliary support featuremark, and wherein the acute angle between the straight line XY and thedirection of normal to the layering plane is from about 45 degrees toabout 90 degrees.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; and (b) direct an energy beam from anenergy source to the powder bed to transform at least a portion of thepowder material to a transformed material that subsequently hardens toyield the three-dimensional object that (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, and (ii) comprises an auxiliarysupport feature or auxiliary support feature mark that is indicative ofa presence or removal of the auxiliary support feature, wherein thelayered structure has a layering plane, wherein X is a point residing onthe surface of the three dimensional object and Y is the closestauxiliary support feature or auxiliary support feature mark to X,wherein Y is spaced apart from X by at least about 10.5 millimeters ormore; wherein the sphere of radius XY is devoid of auxiliary supportfeature or auxiliary support feature mark that is indicative of apresence or removal of the auxiliary support feature, wherein the acuteangle between the straight line XY and the direction of normal to thelayering plane is from about 45 degrees to about 90 degrees.

In another aspect, a three-dimensional object formed by athree-dimensional printing process, comprises a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, and (ii) comprises an auxiliarysupport feature or auxiliary support feature mark that is indicative ofa presence or removal of the auxiliary support feature, wherein thelayered structure has a layering plane, wherein X is a point residing onthe surface of the three dimensional object and Y is the closestauxiliary support feature or auxiliary support feature mark to X,wherein Y is spaced apart from X by at least about 10.5 millimeters ormore; wherein the sphere of radius XY is devoid of auxiliary supportfeature or auxiliary support feature mark, wherein the acute anglebetween the straight line XY and the direction of normal to the layeringplane is from about 45 degrees to about 90 degrees, and wherein thethree dimensional object comprises elemental metal, metal alloy, ceramicor an allotrope of elemental carbon. X may be spaced apart from Y by atleast about 10 millimeters or more.

In another aspect, an apparatus for generating a three-dimensionalobject comprises an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,wherein N is a layering plane of the layered structure, wherein X and Yare points residing on the surface of the three dimensional object,wherein X is spaced apart from Y by at least about 10.5 millimeters ormore, wherein the sphere of radius XY that is centered at X lacksauxiliary support feature or auxiliary support feature mark that isindicative of a presence or removal of the auxiliary support feature,and wherein the acute angle between the straight line XY and thedirection of normal to N is from about 45 degrees to about 90 degrees.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: supply a layer of powdermaterial from a powder dispensing member to a powder bed operativelycoupled to the powder dispensing member, wherein the powder materialcomprises an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; and direct an energy beam from an energy source to thepowder bed to transform at least a portion of the powder material to atransformed material that subsequently hardens to yield thethree-dimensional object that is devoid of surface features indicativeof layer removal during or after the three-dimensional printing process,wherein N is a layering plane of the layered structure, wherein X and Yare points residing on the surface of the three dimensional object,wherein X is spaced apart from Y by at least about 10.5 millimeters ormore, wherein the sphere of radius XY that is centered at X lacksauxiliary support feature or auxiliary support feature mark that isindicative of a presence or removal of the auxiliary support feature,and wherein the acute angle between the straight line XY and thedirection of normal to N is from about 45 degrees to about 90 degrees.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, wherein N is a layering plane of thelayered structure, wherein X and Y are points residing on the surface ofthe three dimensional object, wherein X is spaced apart from Y by atleast about 10.5 millimeters or more, wherein the sphere of radius XYthat is centered at X lacks auxiliary support feature or auxiliarysupport feature mark that is indicative of a presence or removal of theauxiliary support feature, and wherein the acute angle between thestraight line XY and the direction of normal to N is from about 45degrees to about 90 degrees. In some cases, B is spaced apart from C byat least about 10 millimeters or more.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; and (b) direct an energy beam from anenergy source to the powder bed to transform at least a portion of thepowder material to a transformed material that subsequently hardens toyield the three-dimensional object that (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of at least about one centimeter squared (cm²), and(iii) is devoid of one or more auxiliary support features or auxiliarysupport feature marks that are indicative of a presence or removal ofthe auxiliary support feature, and wherein any two metals residingwithin the layer are incapable of forming a eutectic alloy.

In another aspect, an apparatus for generating a three-dimensionalobject comprises an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,(ii) has an exposed layer surface with a surface area of at least aboutone centimeter squared (cm²), and (iii) is devoid of one or moreauxiliary support features or auxiliary support feature marks that areindicative of a presence or removal of the auxiliary support feature,and wherein any two metals residing within the layer are incapable offorming a eutectic alloy.

In another aspect, a three-dimensional object formed by athree-dimensional printing process, comprising a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of at least about one centimeter squared (cm²), and(iii) is devoid of one or more auxiliary support features or auxiliarysupport feature marks that are indicative of a presence or removal ofthe auxiliary support feature, and wherein any two metals residingwithin the layer are incapable of forming a eutectic alloy.

In another aspect, an apparatus for forming a three-dimensional object,comprising a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; and (b) direct an energy beam from anenergy source to the powder bed to transform at least a portion of thepowder material to a transformed material that subsequently hardens toyield the three-dimensional object that (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of at least about one centimeter squared (cm²), and(iii) is devoid of one or more auxiliary support features or auxiliarysupport feature marks that are indicative of a presence or removal ofthe auxiliary support feature, and wherein each layer of the threedimensional object comprises at most substantially a single elementalmetal.

In another aspect, an apparatus for generating a three-dimensionalobject comprises: an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,(ii) has an exposed layer surface with a surface area of at least aboutone centimeter squared (cm²), and (iii) is devoid of one or moreauxiliary support features or auxiliary support feature marks that areindicative of a presence or removal of the auxiliary support feature,and wherein each layer of the three dimensional object comprises at mostsubstantially a single elemental metal.

In another aspect, a three-dimensional object formed by athree-dimensional printing process comprises a layered structurecomprising successive solidified melt pools of a material that comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon, wherein the three-dimensional object (i) is devoid of surfacefeatures indicative of layer removal during or after thethree-dimensional printing process, (ii) has an exposed layer surfacewith a surface area of at least about one centimeter squared (cm²), and(iii) is devoid of one or more auxiliary support features or auxiliarysupport feature marks that are indicative of a presence or removal ofthe auxiliary support feature, and wherein each layer of the threedimensional object comprises at most substantially a single elementalmetal.

The layered structure can comprise substantially repetitive layers. Thelayers can have an average layer size of at most about 500 μm or less.The layered structure can be indicative of layered deposition. Thelayered structure can be indicative of solidification of melt poolsformed during a three dimensional printing process. The structureindicative of a three dimensional printing process can comprisesubstantially repetitive variation comprising: variation in grainorientation, variation in material density, variation in the degree ofcompound segregation to grain boundaries, variation in the degree ofelement segregation to grain boundaries, variation in material phase,variation in metallurgical phase, variation in material porosity,variation in crystal phase, or variation in crystal structure. Thelayered structure can comprise substantially repetitive layers, whereinthe layers have an average layer size of at least about 5 μm or more.The melt pools are indicative of a additive manufacturing processcomprising selective laser melting (SLM), selective laser sintering(SLS), direct metal laser sintering (DMLS), or fused deposition modeling(FDM). The melt pools may be indicative of an additive manufacturingprocess comprising selective laser melting. The melt pools may comprisecrystals. The melt pools may comprise single crystals.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to supply a layer of powdermaterial from a powder dispensing member to a powder bed operativelycoupled to the powder dispensing member, wherein the powder materialcomprises an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; and direct an energy beam from an energy source to thepowder bed to transform at least a portion of the powder material to atransformed material that subsequently hardens into a hardened materialto yield the three-dimensional object that is suspended in the powderbed, wherein at least one layer of the hardened material has a radius ofcurvature of at least about 50 centimeters as measured by opticalmicroscopy, and wherein the powder bed is devoid of a supportingscaffold substantially enclosing the three-dimensional object.

In another aspect, an apparatus for generating a three-dimensionalobject comprises an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form ahardened material that is at least a portion of a three-dimensionalobject, wherein upon formation the three-dimensional object is suspendedin the powder bed, wherein at least one layer of hardened material has aradius of curvature of at least about 50 centimeters as measured byoptical microscopy, and wherein the powder bed is devoid of a supportingscaffold substantially enclosing the three-dimensional object.

In another aspect, a method for generating a three-dimensional objectsuspended in a powder bed comprises: (a) providing the powder bed in anenclosure, wherein the powder bed comprises a powder material having anelemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; (b) transforming at least a portion of the powder material intoa transformed material; and (c) hardening the transformed material toform at least one layer of hardened material as part of thethree-dimensional object, which three-dimensional object is suspended inthe powder bed, wherein the at least one layer of hardened material hasa radius of curvature of at least about 50 centimeters as measured byoptical microscopy, and wherein the powder bed is devoid of a supportingscaffold substantially enclosing the three-dimensional object.

The supporting scaffold can be a sintered structure. The at least onelayer of hardened material can have a radius of curvature of one meteror more. The layer of hardened material can be devoid of at least twometals that form a eutectic alloy. The layer of hardened material cancomprise at most a metal that can be of a single elemental metalcomposition. The layer of hardened material can comprise a metal alloythat can be of a single metal alloy composition. The layer of hardenedmaterial can be of a single material composition. A fundamental lengthscale of the three-dimensional object can be about 120 micrometers ormore. The three-dimensional object can be non-supported by one or moreauxiliary support features in the powder bed. The three-dimensionalobject can be devoid of auxiliary support features. Thethree-dimensional object can comprise one or more auxiliary supportfeatures that are suspended in the powder bed. The transformingoperation can be performed according to a model of the three-dimensionalobject, and wherein the three-dimensional object deviates from the modelby at most about 50 micrometers. The transforming operation can comprisefusing individual particles of the powder material. Fusing can comprisesintering or melting the individual particles. The hardening cancomprise solidifying the transformed material.

The powder material can comprise an elemental metal or metal alloy. Thepowder material can be provided adjacent to a base that can bepositioned within the enclosure. In some embodiments, upon formation ofthe at least one layer of hardened material, the three-dimensionalobject is not in contact with the base.

In another aspect, a system for generating a three-dimensional objectsuspended in a powder bed comprises: an enclosure that accommodates thepowder bed, wherein the powder bed comprises a powder material having anelemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; an energy source that provides an energy beam to the powdermaterial in the powder bed; and a controller operatively coupled to theenergy source and programmed to (i) receive instructions to generate atleast a portion of the three-dimensional object and (ii) direct theenergy beam along a predetermined path in accordance with theinstructions to transform at least a portion of the powder material to atransformed material that hardens to form at least one layer of hardenedmaterial as part of the three-dimensional object, whichthree-dimensional object is suspended in the powder bed, wherein the atleast one layer of hardened material has a radius of curvature of atleast about 50 centimeters as measured by optical microscopy, andwherein upon formation of the at least one layer of hardened material,the powder bed is devoid of a supporting scaffold substantiallyenclosing the three-dimensional object.

The powder material can be disposed adjacent to a base that can bepositioned within the enclosure. In some instances, upon the transformedmaterial hardening into the three-dimensional object, thethree-dimensional object is not in contact with the base. Thethree-dimensional object can be devoid of auxiliary support features.The supporting scaffold may extend over at least about one millimeter.The powder bed can be devoid of a supporting scaffold substantiallyenclosing the three-dimensional object The at least one layer ofhardened material can be devoid of at least two metals that form aeutectic alloy. The energy beam can comprise an electromagnetic energybeam, a charged particle beam, or a non-charged particle beam. Theenergy beam can comprise an electromagnetic energy beam. The system mayfurther comprise a heat sink for removing heat from the powder bed, andwherein the heat sink can be disposed within the enclosure. In someinstances, upon formation of the at least one layer of hardenedmaterial, at least about 30 percent of the heat removal occurs from thetop surface of the powder bed using the heat sink. In some instances,upon formation of the at least one layer of hardened material, at leastabout 20%, 25%, 30%, 35%, 40%, 45%. 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, or 95% of the heat removal occurs from the top surface of thepowder bed using the heat sink. The powder material can be disposedadjacent to the base, and wherein the heat sink does not contact a basethat can be positioned within the enclosure. The heat sink can bedisposed adjacent to an exposed surface of the powder bed. The heat sinkcan be disposed along a path of the energy beam that extends from theenergy source to the powder bed. The heat sink can be separated from thepowder bed by a gap. The at least a portion of the three dimensionalobject deviates from the model by at most the sum of 25 micrometers and1/1000 of a fundamental length scale of the three dimensional object.Hardening can comprise allowing the transformed material to solidify.The transforming operation can comprise selectively transforming theportion of the powder material by directing a beam of laser light at theportion of the powder material. The system may further comprise heatinga portion of a remainder of the powder material that did not fuse toform at least a portion of the three dimensional object by directingenergy to the portion of the remainder. The energy can be directed usinga laser beam. The powder material can comprise individual particles ofparticles sizes that are less than or equal to about 500 nanometers(nm). Transforming can be conducted according to a predetermined patternthat corresponds to a model of the three dimensional object.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to supply a layer of powdermaterial from a powder dispensing member to a powder bed operativelycoupled to the powder dispensing member, wherein the powder materialcomprises an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; and direct an energy beam from an energy source to thepowder bed to transform at least a portion of the powder material to atransformed material that subsequently hardens to yield thethree-dimensional object that is devoid of the auxiliary supportfeatures, wherein the three-dimensional object has a radius of curvatureof at least about 50 centimeters as measured by optical microscopy.

In another aspect, an apparatus for generating a three-dimensionalobject comprises an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object is devoid of the auxiliary support features,wherein the three-dimensional object has a radius of curvature of atleast about 50 centimeters as measured by optical microscopy.

In another aspect, a method for generating a three-dimensional objectdevoid of auxiliary support features comprises: (a) providing a powderbed in an enclosure, wherein the powder bed comprises a powder materialhaving an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; (b) transforming a portion of the powder material intoa transformed material; and (c) hardening the transformed material toform the three-dimensional object that is devoid of the auxiliarysupport features, wherein the three-dimensional object has a radius ofcurvature of at least about 50 centimeters as measured by opticalmicroscopy.

The auxiliary support can comprise a supporting scaffold substantiallyenclosing the three-dimensional object. The supporting scaffold cancomprise a sintered structure. The three-dimensional object has a radiusof curvature of about one meter or more. The three-dimensional objectcan be devoid of at least two metals that form a eutectic alloy. Thethree-dimensional object can comprise a metal that can be at most of asingle elemental metal composition. The three-dimensional object cancomprise a metal alloy that can be of a single metal alloy composition.The three-dimensional object can be of a single material composition. Afundamental length scale of the three-dimensional object can be at leastabout 120 micrometers. The transforming can comprise fusing individualparticles of the powder material. Fusing can comprise sintering ormelting the individual particles. Hardening can comprise solidifying thetransformed material. Transforming can comprise directing an energy beamat the portion of the powder material along a path that can be generatedaccording to a model of the three-dimensional object. The powdermaterial can be provided adjacent to a base within the enclosure, andwherein upon the transformed material hardening into thethree-dimensional object, the three-dimensional object can be not incontact with the base.

In another aspect, a system for generating a three-dimensional objectdevoid of auxiliary support features comprises: an enclosure thataccommodates the powder bed, wherein the powder bed comprises a powdermaterial having an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; an energy source that provides an energybeam to the powder material in the powder bed; and a controlleroperatively coupled to the energy source and programmed to (i) receiveinstructions to generate the three-dimensional object and (ii) directthe energy beam along a path in accordance with the instructions totransform a portion of the powder material to a transformed materialthat hardens to form the three-dimensional object that is devoid of theauxiliary support features, and wherein the three-dimensional object hasa radius of curvature of at least about 50 centimeters as measured byoptical microscopy.

The powder material can be disposed adjacent to a base within theenclosure, and wherein the three-dimensional object can be not incontact with the base. The auxiliary support can comprise a supportingscaffold that substantially encloses the three-dimensional object. Thesupporting scaffold can be a sintered structure. The three-dimensionalobject has a radius of curvature of about one meter or more. Thethree-dimensional object can be devoid of at least two metals that forma eutectic alloy. The path can be generated from a model of thethree-dimensional object. The system may further comprise a heat sinkfor removing heat from the powder bed, and wherein the heat sink can bedisposed within the enclosure. In some embodiments, upon the transformedmaterial hardening into the three-dimensional object, at least about 30percent of heat removal occurs from the top surface of the powder bedusing the heat sink. The powder material can be disposed adjacent to abase, and wherein the heat sink does not contact the base. The heat sinkcan be disposed adjacent to an exposed surface of the powder bed. Theheat sink can be disposed along a path of the energy beam that extendsfrom the energy source to the powder bed. The heat sink can be separatedfrom the powder bed by a gap.

In another aspect, a method for generating a three dimensional objectcomprises: (a) providing a powder bed in an enclosure, wherein thepowder bed comprises a powder material having an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; (b) transforming aportion of the powder material into a transformed material; and (c)hardening the transformed material to form at least one layer ofhardened material as part of the three-dimensional object, wherein theat least one layer of hardened material has a radius of curvature of atleast about 50 centimeters as measured by optical microscopy, andwherein, with X and Y being points on a surface of the three-dimensionalobject, (i) the surface of the three-dimensional object along a sphereof radius XY is devoid of auxiliary support features, and (ii) an acuteangle between a straight line XY and a direction normal to an averagelayering plane (N) of the at least one layer of hardened material isfrom about 45 degrees to 90 degrees when X and Y are spaced apart by atleast about 2 millimeters.

The acute angle between the straight line XY and the direction normal toN of the at least one layer of hardened material can be from about 45degrees to 90 degrees when X and Y are spaced apart by at least about10.5 millimeters. The acute angle between the straight line XY and thedirection normal to N of the at least one layer of hardened material canbe from about 45 degrees to 90 degrees when X and Y are spaced apart byat least about 40.5 millimeters. The powder bed can be devoid of asupporting scaffold substantially enclosing the three-dimensionalobject. The supporting scaffold can comprise a sintered structure. Theat least one layer of hardened material may have a radius of curvatureof at least about one meter. The at least one layer of hardened materialcan be devoid of at least two metals that form a eutectic alloy. The atleast one layer of hardened material can comprise at most a metal thatcan be of a single elemental metal composition. The at least one layerof hardened material can comprise a metal alloy that can be of a singlemetal alloy composition. The at least one layer of hardened material canbe of a single material composition. The method may further compriserepeating (a) to (c). A fundamental length scale of the threedimensional object can be about 120 micrometers or more. The threedimensional object can be devoid of auxiliary support features. Thethree-dimensional object can comprise auxiliary support features thatare suspended in the powder bed. The acute angle between the straightline XY and the direction of normal to N can be from about 60 degrees toabout 90 degrees (e.g., when X and Y are spaced apart by at least about2 millimeters). The transforming can comprise fusing individualparticles of the powder material. Fusing can comprise sintering ormelting the individual particles. Hardening can comprise solidifying thetransformed material. Transforming the powder material can comprisedirecting an energy beam at the portion of the powder material along apath that can be generated according to a model of the three-dimensionalobject. Transforming can be conducted according to a model of thethree-dimensional object, and wherein the three-dimensional objectdeviates from the model by about 50 micrometers or less. The powdermaterial can be disposed adjacent to a base that can be positionedwithin the enclosure, and wherein upon formation of the at least onelayer of a hardened material, the three-dimensional object can be not incontact with the base. The method may further comprise repeatingoperations (a) to (c), wherein a subsequent layer of powder material canbe provided on a previously provided layer of powder material. Theremainder of the powder material that did not transform to form at leasta part of the three dimensional object, can be devoid of a continuousstructure extending over about 0.5 millimeter or more. The method mayfurther comprise separating the at least a portion of the threedimensional object from the remainder of the powder material that didnot transform to form at least a part of the three dimensional object.The three dimensional object and the remainder may be removed from abase on which the powder material can be disposed within the enclosure.Operations (a)-(c) may be performed at a pressure of at least 10⁻⁶ Torr.Operations (a)-(c) may be performed at a pressure of at most 10⁻¹ Torror more. The powder material can be devoid of two or more metals at aratio that can form a eutectic alloy. A remainder of the powder materialthat did not form the at least a part of the three dimensional object,can be devoid of a continuous structure extending over about 1millimeter or more. A remainder of the powder material that did not formthe at least a part of the three dimensional object, can be devoid of ascaffold enclosing the three dimensional object. The solidus temperatureof the material can be less than or equal to about 400° C. The liquidustemperature of the material can be greater than or equal to about 300°C. In some examples, in operation (b) the powder material can betransforming excludes sintering.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; an energy sourcethat provides an energy beam to the powder material in the powder bed;and a controller operatively coupled to the energy source and programmedto (i) receive instructions to generate at least a portion of thethree-dimensional object and (ii) direct the energy beam along a path inaccordance with the instructions to transform a portion of the powdermaterial to a transformed material that hardens to form at least onelayer of a hardened material as part of the three-dimensional object,wherein the at least one layer of hardened material has a radius ofcurvature of at least about 50 centimeters as measured by opticalmicroscopy, and wherein, X and Y being points on a surface of thethree-dimensional object, (i) the surface of the three-dimensionalobject along a sphere of radius XY is devoid of auxiliary supportfeatures, and (ii) an acute angle between a straight line XY and adirection normal to an average layering plane (N) of the at least onelayer of hardened material is from about 45 degrees to 90 degrees when Xand Y are spaced apart by about 2 millimeters or more.

In some embodiments, upon formation of the at least one layer of ahardened material, the three dimensional object can be suspended in thepowder bed. In some embodiments, the powder material can be disposedadjacent to a base that can be positioned within the enclosure. In someembodiments, upon formation of the at least one layer of a hardenedmaterial, the three-dimensional object can be not in contact with thebase. In some embodiments, upon formation of the at least one layer ofhardened material, the powder bed can be devoid of a supporting scaffoldsubstantially enclosing the three-dimensional object. The supportingscaffold can comprise a sintered structure. The at least one layer ofhardened material has a radius of curvature of about one meter or more.The energy beam can comprise an electromagnetic beam, a charged electronbeam, or a non-charged electron beam. The system may further comprise aheat sink for removing heat from the powder bed. The path can begenerated from a model of the three-dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises: (a) providing a powder bed in an enclosure, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; (b) transforming a portion of the powder materialinto a transformed material; and (c) hardening the transformed materialto form at least one layer of hardened material as part of thethree-dimensional object, wherein the three-dimensional object (i) isdevoid of surface features indicative of layer removal during or afterthe three-dimensional printing process, and (ii) is devoid of one ormore auxiliary support features or auxiliary support feature marks thatare indicative of a presence or removal of the auxiliary supportfeature.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; an energy source that provides an energy beam tothe powder material in the powder bed; and a controller operativelycoupled to the energy source and programmed to (i) receive instructionsto generate at least a portion of the three-dimensional object and (ii)direct the energy beam along a predetermined path in accordance with theinstructions to transform a portion of the powder material to atransformed material that hardens to form at least one layer of ahardened material as part of the three-dimensional object, wherein thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,and (ii) is devoid of one or more auxiliary support features orauxiliary support feature marks that are indicative of a presence orremoval of the auxiliary support feature.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing a powder bed in an enclosure, wherein the powderbed comprises a powder material having an elemental metal, metal alloy,ceramic, or an allotrope of elemental carbon; (b) transforming a portionof the powder material into a transformed material; and (c) hardeningthe transformed material to form at least one layer of hardened materialas part of the three-dimensional object, wherein the at least one layerof hardened material has a radius of curvature of at least about 50centimeters as measured by optical microscopy, wherein thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,and (ii) comprises two auxiliary support features or auxiliary supportfeature marks that are indicative of a presence or removal of theauxiliary support features, wherein the layered structure has a layeringplane, wherein the two auxiliary supports or auxiliary support marks arespaced apart by at least about 40.5 millimeters or more; and wherein theacute angle between the straight line connecting the two auxiliarysupports or auxiliary support marks and the direction of normal to thelayering plane is from about 45 degrees to about 90 degrees.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; an energy sourcethat provides an energy beam to the powder material in the powder bed;and a controller operatively coupled to the energy source and programmedto (i) receive instructions to generate at least a portion of thethree-dimensional object and (ii) direct the energy beam along apredetermined path in accordance with the instructions to transform aportion of the powder material to a transformed material that hardens toform at least one layer of a hardened material as part of thethree-dimensional object, wherein the at least one layer of hardenedmaterial has a radius of curvature of at least about 50 centimeters asmeasured by optical microscopy, wherein the three-dimensional object (i)is devoid of surface features indicative of layer removal during orafter the three-dimensional printing process, and (ii) comprises twoauxiliary support features or auxiliary support feature marks that areindicative of a presence or removal of the auxiliary support features,wherein the layered structure has a layering plane, wherein the twoauxiliary support features or the two auxiliary support marks are spacedapart by at least about 40.5 millimeters or more, and wherein the acuteangle between the straight line connecting the two auxiliary supportfeatures or auxiliary support marks and the direction of normal to thelayering plane is from about 45 degrees to about 90 degrees.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing a powder bed in an enclosure, wherein the powderbed comprises a powder material having an elemental metal, metal alloy,ceramic, or an allotrope of elemental carbon; (b) transforming a portionof the powder material into a transformed material; and (c) hardeningthe transformed material to form at least one layer of hardened materialas part of the three-dimensional object, wherein the at least one layerof hardened material has a radius of curvature of at least about 50centimeters as measured by optical microscopy, wherein thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,and (ii) comprises an auxiliary support feature or an auxiliary supportmark that is indicative of a presence or removal of the auxiliarysupport feature, wherein the layered structure has a layering plane,wherein X is a point residing on the surface of the three dimensionalobject and Y is the closest auxiliary support mark to X, wherein Y isspaced apart from X by at least about 10.5 millimeters or more; whereinthe sphere of radius XY is devoid of the auxiliary support feature orauxiliary support mark, wherein the acute angle between the straightline XY and the direction of normal to the layering plane is from about45 degrees to about 90 degrees, and wherein the three dimensional objectcomprises elemental metal, metal alloy, ceramic or an allotrope ofelemental carbon.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; an energy sourcethat provides an energy beam to the powder material in the powder bed;and a controller operatively coupled to the energy source and programmedto (i) receive instructions to generate at least a portion of thethree-dimensional object and (ii) direct the energy beam along apredetermined path in accordance with the instructions to transform aportion of the powder material to a transformed material that hardens toform at least one layer of a hardened material as part of thethree-dimensional object, wherein the at least one layer of hardenedmaterial has a radius of curvature of at least about 50 centimeters asmeasured by optical microscopy, wherein the three-dimensional object (i)is devoid of surface features indicative of layer removal during orafter the three-dimensional printing process, and (ii) comprises anauxiliary support feature or auxiliary support mark that is indicativeof a presence or removal of the auxiliary support feature, wherein thelayered structure has a layering plane, wherein X is a point residing onthe surface of the three dimensional object and Y is the closestauxiliary support mark to X, wherein Y is spaced apart from X by atleast about 10.5 millimeters or more; wherein the sphere of radius XY isdevoid of the auxiliary support feature or auxiliary support mark,wherein the acute angle between the straight line XY and the directionof normal to the layering plane is from about 45 degrees to about 90degrees, and wherein the three dimensional object comprises elementalmetal, metal alloy, ceramic or an allotrope of elemental carbon.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing a powder bed in an enclosure, wherein the powderbed comprises a powder material having an elemental metal, metal alloy,ceramic, or an allotrope of elemental carbon; (b) transforming a portionof the powder material into a transformed material; and (c) hardeningthe transformed material to form at least one layer of hardened materialas part of the three-dimensional object, wherein the at least one layerof hardened material has a radius of curvature of at least about 50centimeters as measured by optical microscopy, wherein thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,(ii) has an exposed layer surface with a surface area of at least aboutone centimeter squared (cm²), and (iii) is devoid of one or moreauxiliary support features or auxiliary support feature marks that areindicative of a presence or removal of the auxiliary support feature,and wherein any two metals residing within the layer are incapable offorming a eutectic alloy.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; an energy sourcethat provides an energy beam to the powder material in the powder bed;and a controller operatively coupled to the energy source and programmedto (i) receive instructions to generate at least a portion of thethree-dimensional object and (ii) direct the energy beam along apredetermined path in accordance with the instructions to transform aportion of the powder material to a transformed material that hardens toform at least one layer of a hardened material as part of thethree-dimensional object, wherein the at least one layer of hardenedmaterial has a radius of curvature of at least about 50 centimeters asmeasured by optical microscopy, wherein the three-dimensional object (i)is devoid of surface features indicative of layer removal during orafter the three-dimensional printing process, (ii) has an exposed layersurface with a surface area of at least about one centimeter squared(cm²), and (iii) is devoid of one or more auxiliary support features orauxiliary support feature marks that are indicative of a presence orremoval of the auxiliary support feature, and wherein any two metalsresiding within the layer are incapable of forming a eutectic alloy.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing a powder bed in an enclosure, wherein the powderbed comprises a powder material having an elemental metal, metal alloy,ceramic, or an allotrope of elemental carbon; (b) transforming a portionof the powder material into a transformed material; and (c) hardeningthe transformed material to form at least one layer of hardened materialas part of the three-dimensional object, wherein the at least one layerof hardened material has a radius of curvature of at least about 50centimeters as measured by optical microscopy, wherein thethree-dimensional object (i) is devoid of surface features indicative oflayer removal during or after the three-dimensional printing process,(ii) has an exposed layer surface with a surface area of at least aboutone centimeter squared (cm²), and (iii) is devoid of one or moreauxiliary support features or auxiliary support feature marks that areindicative of a presence or removal of the auxiliary support feature,and wherein each layer of the three dimensional object comprises at mostsubstantially a single elemental metal.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; an energy sourcethat provides an energy beam to the powder material in the powder bed;and a controller operatively coupled to the energy source and programmedto (i) receive instructions to generate at least a portion of thethree-dimensional object and (ii) direct the energy beam along apredetermined path in accordance with the instructions to transform aportion of the powder material to a transformed material that hardens toform at least one layer of a hardened material as part of thethree-dimensional object, wherein the three-dimensional object (i) isdevoid of surface features indicative of layer removal during or afterthe three-dimensional printing process, (ii) has an exposed layersurface with a surface area of at least about one centimeter squared(cm²), and (iii) is devoid of one or more auxiliary support features orauxiliary support feature marks that are indicative of a presence orremoval of the auxiliary support feature, and wherein each layer of thethree dimensional object comprises at most substantially a singleelemental metal.

The at least one layer of hardened material may have a radius ofcurvature of at least about 50 centimeters as measured by opticalmicroscopy. The at least one layer of hardened material may have aradius of curvature of at least about 50 centimeters as measured byoptical microscopy.

In another aspect, a method for generating a three-dimensional objectdevoid of auxiliary support features comprises (a) providing a powderbed in an enclosure, wherein the powder bed comprises a powder materialhaving an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; (b) transforming a portion of the powder material intoa transformed material; and (c) hardening the transformed material toform the three-dimensional object that is devoid of the auxiliarysupport features, wherein the three-dimensional object is devoid of atleast two metals that form a eutectic alloy.

The solidified material can be formed within a deviation from thedesigned three dimensional structure of at most about the sum of 25micrometers and one thousandths of a fundamental length scale of thethree dimensional object. The solidified material can be formed within adeviation from the designed three dimensional structure of at most aboutthe sum of 25 micrometers and 1/2500 of a fundamental length scale ofthe three dimensional object. Operations (a)-(c) can be performed at apressure that can be greater than about 10⁻⁶ Torr. Operations (a)-(c)can be performed at a pressure that can be greater than or equal toabout 10⁻¹ Torr. The methods disclosed herein may further compriseremoving the solidified material from the powder material that did notfuse to form at least a part of the three dimensional object.

In another aspect, a system for generating a three-dimensional objectdevoid of auxiliary support features comprises an enclosure thataccommodates the powder bed, wherein the powder bed comprises a powdermaterial having an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; an energy source that provides an energybeam to the powder material in the powder bed; and a controlleroperatively coupled to the energy source and programmed to (i) receiveinstructions to generate the three-dimensional object and (ii) directthe energy beam along a path in accordance with the instructions totransform a portion of the powder material to a transformed materialthat hardens to form the three-dimensional object that is devoid of theauxiliary support features, and wherein the three-dimensional object isdevoid of at least two metals that form a eutectic alloy.

The auxiliary support can comprise a scaffold enclosing thethree-dimensional object. The three dimensional object can comprise asingle elemental metal composition. The three dimensional object can bedevoid of an elemental metal. The powder material can be devoid of morethan one metal. The three dimensional object can be devoid of more thanone metal. The powder material can be devoid of two or more metals at aratio that form a eutectic alloy.

In another aspect, a method for generating a three-dimensional objectdevoid of auxiliary support features comprises (a) providing a powderbed in an enclosure, wherein the powder bed comprises a powder materialhaving an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; (b) heating a portion of the layer of the powdermaterial to a temperature that is at least a melting temperature of thepowder material to form a molten material, wherein during the heating, aportion of a remainder of the powder material that was not heated to atleast a melting temperature, is at a temperature that is below asintering temperature of the powder material; and (c) solidifying themolten material to form at least part of the three-dimensional objectthat is devoid of the auxiliary support features, wherein thethree-dimensional object is devoid of at least two metals that form aeutectic alloy.

The powder material can be devoid of two or more metals that form aeutectic alloy. In some instances, a remainder of the powder materialthat did not fuse and solidify to form at least a part of the threedimensional object, can be devoid of a continuous structure extendingover about 1 millimeter or more. In some instances, a remainder of thepowder material that did not fuse and solidify to form at least a partof the three dimensional object, can be devoid of a scaffold thatencloses the three dimensional structure. The method may furthercomprise providing an additional layer of powder material adjacent tothe layer subsequent to (c). The method may further comprise repeatingoperations (a) to (c). The method may further comprise cooling theportion and the remainder of the powder material that did not melt andsolidify to form at least a portion of the three dimensional object. Theportion and the remainder may be cooled at substantially the same rate.

The melting temperature can be at least about 400° C. or more and thesintering temperature can be at most about 400° C. or less. The meltingtemperature can be at least about 400° C. or more and the sinteringtemperature can be at most about 300° C. or less. The method may furthercomprise separating the remainder of the layer that did not fuse andsolidify to form at least a portion of the three dimensional object,from the portion. The method may further comprise delivering the threedimensional object to a customer. The method may further comprisepackaging the three dimensional object.

In another aspect, a system for generating a three-dimensional objectdevoid of auxiliary support features comprises an enclosure thataccommodates the powder bed, wherein the powder bed comprises a powdermaterial having an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; an energy source that provides an energybeam to the powder material in the powder bed; and a controlleroperatively coupled to the energy source and programmed to (i) receiveinstructions to generate the three-dimensional object and (ii) directthe energy beam along a path in accordance with the instructions to heatand melt a portion of the powder material to a molten material thatsolidifies into the three-dimensional object that is devoid of theauxiliary support features, wherein a portion of a remainder of thepowder material that was not heated to at least a melting temperature,is at a temperature that is below a sintering temperature of the powdermaterial, and wherein the three-dimensional object is devoid of at leasttwo metals that form a eutectic alloy.

In another aspect, an apparatus for selectively fusing powder materialcomprises a controller configured to: (a) control the provision of alayer of the powder material to a part bed from a powder materialdeposition device, wherein the powder material comprises elementalmetal, metal alloy, ceramic or elemental carbon; (b) control theprovision of radiation to fuse at least a portion of the powder materialof the layer; (c) control the provision of an additional layer of powdermaterial overlying the prior layer of particulate material, includingthe previously fused portion of material from the particulate materialdeposition device; (d) control the provision of radiation to fuse afurther portion of the material within the overlying further layer andto fuse said further portion with the previously fused portion ofmaterial in the prior layer; and (e) control the successive repeating ofoperations (c) and (d) to form a three dimensional object, wherein thethree dimensional object is formed without auxiliary supports.

In another aspect, a method for generating a three dimensional objectcomprises (a) receiving a request for generation of a requested threedimensional object from a customer, wherein the requested threedimensional object comprises an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; (b) additively generating agenerated three dimensional object according to a model of the threedimensional object; and (c) delivering the generated three dimensionalobject to the customer, wherein operation (b)-(c) are performed withoutremoval of auxiliary features, wherein the generated three dimensionalobject is substantially identical to the requested three dimensionalobject.

The generated three dimensional object may deviate from the requestedthree dimensional object by at most about the sum of 25 micrometers and1/1000 times the fundamental length scale of the requested threedimensional object. The generated three dimensional object may deviatefrom the requested three dimensional object by at most about the sum of25 micrometers and 1/2500 times the fundamental length scale of therequested three dimensional object.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: supply a layer of powdermaterial from a powder dispensing member to a powder bed operativelycoupled to the powder dispensing member, wherein the powder materialcomprises an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; and direct an energy beam from an energy source to thepowder bed to transform at least a portion of the powder material to atransformed material that subsequently hardens to yield thethree-dimensional object that is delivered to a customer without removalof auxiliary features, wherein the generated three dimensional object issubstantially identical to the three dimensional object requested by thecustomer.

In another aspect, an apparatus for generating a three-dimensionalobject comprises an enclosure that accommodates a powder bed comprisingthe powder material comprising an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; and an energy source that providesan energy beam to the powder material in the powder bed to form at leasta portion of a three-dimensional object, wherein upon formation thethree-dimensional object is delivered to a customer without removal ofauxiliary features, wherein the generated three dimensional object issubstantially identical to the three dimensional object requested by thecustomer.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; an energy source that provides an energy beam tothe powder material in the powder bed; and a controller operativelycoupled to the energy source and programmed to (i) receive instructionsto generate a desired three-dimensional object according to a customerrequest, and (ii) direct the energy beam along a predetermined path inaccordance with the instructions to transform a portion of the powdermaterial to a transformed material that hardens to form at least onelayer of a hardened material as part of the generated three-dimensionalobject, wherein the generated three-dimensional object is delivered tothe customer without removal of auxiliary features, wherein thegenerated three dimensional object is substantially identical to therequested three dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) receiving a request for generation of a requested threedimensional object from a customer, wherein the requested threedimensional object comprises an elemental metal, metal alloy, ceramic,or an allotrope of elemental carbon; (b) additively generating agenerated three dimensional object according to a model of the requestedthree dimensional object; and (c) delivering the generated threedimensional object to the customer, wherein operation (b) is performedwithout usage of auxiliary features; wherein the remainder of the powdermaterial that did not form the three dimensional object, is devoid of ascaffold structure that encloses the generated three dimensional objet,and wherein the generated three dimensional object is substantiallyidentical to the requested three dimensional object.

The powder material can be devoid of two or more metals at a ratio thatcan form at least one eutectic alloy. The request can comprise the modelof the three dimensional object. The method may further comprisegenerating the model of the three dimensional object. The model can begenerated from a representative physical model of the three dimensionalobject. The method may further comprise receiving an item of value fromthe customer in exchange for the three dimensional object. The threedimensional object can be additively generated at with a deviation of atmost about 50 micrometers from the model of the three dimensionalobject. The generated three dimensional object may deviate from therequested three dimensional object by at most about the sum of 25micrometers and 1/1000 times the fundamental length scale of therequested three dimensional object. The generated three dimensionalobject may deviate from the requested three dimensional object by atmost about the sum of 25 micrometers and 1/2500 times the fundamentallength scale of the requested three dimensional object. Operations(a)-(c) may be performed in a time period that can be at most about 2days or less. Operations (a)-(c) may be performed in a time period thatcan be at most about 1 days or less. Operations (a)-(c) may be performedin a time period that can be at most about six hours or less. Theadditively generating can comprise successively depositing and fusingthe powder material. The design can be devoid of auxiliary features. Themethod may further comprise transforming the design into instructionsusable by the processor to generate the three dimensional object.Operation (b) can be performed without iterative and/or correctiveprinting. The request can be received from the customer.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; an energy source that provides an energy beam tothe powder material in the powder bed; and a controller operativelycoupled to the energy source and programmed to (i) receive instructionsto generate a desired three-dimensional object according to a customerrequest, and (ii) direct the energy beam along a predetermined path inaccordance with the instructions to transform a portion of the powdermaterial to a transformed material that hardens to form at least onelayer of a hardened material as part of the generated three-dimensionalobject, is devoid of auxiliary features; wherein the remainder of thepowder material that did not form the three dimensional object, isdevoid of a scaffold structure that encloses the generated threedimensional objet, and wherein the generated three dimensional object issubstantially identical to the requested three dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) receiving a request for generation of a three dimensionalobject from a customer, wherein the three dimensional object comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; (b) additively generating the three dimensional object accordingto a model of the three dimensional object; and (c) delivering the threedimensional object to the customer, wherein operations (a)-(c) areperformed in a time period that is about 72 hours or less, and whereinthe three dimensional object is additively generated at a deviation fromthe models of at most about the sum of 50 micrometers plus 1/1000 timesthe fundamental length scale of the three dimensional object.

The request can be accompanied by the model of the three dimensionalobject. The method may further comprise generating the model of thethree dimensional object. The three dimensional object can be additivelygenerated by deviating from the model by at most about the sum of 25micrometers plus 1/1000 times the fundamental length scale of the threedimensional object. The three dimensional object can be additivelygenerated by deviating from the model by at most about the sum of 25micrometers plus 1/2500 times the fundamental length scale of the threedimensional object. The three dimensional object can be additivelygenerated by deviating from the model by at most about 50 micrometers.The three dimensional object can be additively generated by deviatingfrom the model by at most about 25 micrometers. Operations (a)-(c) maybe performed in a time period that can be at most about 48 hours orless. Operations (a)-(c) may be performed in a time period that can beat most about 24 hours or less. Operations (a)-(c) may be performed in atime period that can be at most about 12 hours or less. Operations(a)-(c) may be performed in a time period that can be at most about 6hours or less. Operations (a)-(c) may be performed in a time period thatcan be at most about 1 hour or less. The additively generating cancomprise successively depositing and fusing the powder. The method mayfurther comprise transforming the design into instructions usable by theprocessor to additively generate the three dimensional object. Themethod may further comprise receiving an item of value from the customerin exchange for the three dimensional object. Operation (b) can beperformed without iterative and/or corrective printing. The request canbe received from the customer.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon, wherein the powder bed is disposed withinan enclosure, wherein the pressure in the enclosure is greater thanabout 10⁻⁶ Torr; and (b) direct an energy beam from an energy source tothe powder bed to transform at least a portion of the powder material toa transformed material that subsequently hardens to yield thethree-dimensional object that is generated within a time period that isabout 72 hours or less, wherein the three dimensional object isadditively generated at a deviation from the models of at most about thesum of 50 micrometers plus 1/1000 times the fundamental length scale ofthe three dimensional object.

In another aspect, an apparatus for generating a three-dimensionalobject comprises (a) an enclosure that accommodates a powder bedcomprising the powder material comprising an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon, wherein thepressure in the enclosure is greater than about 10⁻⁶ Torr; and (b) anenergy source that provides an energy beam to the powder material in thepowder bed to form at least a portion of a three-dimensional object,wherein upon formation the three-dimensional object is generated withina time period that is about 72 hours or less, wherein the threedimensional object is additively generated at a deviation from themodels of at most about the sum of 50 micrometers plus 1/1000 times thefundamental length scale of the three dimensional object.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon, wherein the pressure in the enclosure is greaterthan about 10⁻⁶ Torr; an energy source that provides an energy beam tothe powder material in the powder bed; and a controller operativelycoupled to the energy source and programmed to (i) receive instructionsto generate the three-dimensional object according to a customerrequest, and (ii) direct the energy beam along a predetermined path inaccordance with the instructions to transform a portion of the powdermaterial to a transformed material that hardens to form at least onelayer of a hardened material as part of the three-dimensional object,wherein the three dimensional object is generated within a time periodthat is about 72 hours or less, wherein the three dimensional object isadditively generated at a deviation from the models of at most about thesum of 50 micrometers plus 1/1000 times the fundamental length scale ofthe three dimensional object.

In another aspect, a method for generating a three dimensional objectcomprises (a) receiving a request for generation of a three dimensionalobject from a customer, wherein the three dimensional object comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; (b) additively generating the three dimensional object accordingto a model of the three dimensional object; and (c) delivering the threedimensional object to the customer, wherein operation (b) is performedin a time period that is about 12 hours or less from the receiving inoperation (a), and wherein operation (b) is performed at a pressure thatis greater than about 10⁻⁶ Torr.

The request can be accompanied by the model design of the threedimensional object. The method may further comprise generating the modeldesign of the three dimensional object. The three dimensional object canbe additively generated by deviating from the model by at most about 50micrometers or less. The method may further comprise transforming thedesign into instructions usable by the processor to additively generatethe three dimensional object. The method may further comprise receivingan item of value from the customer in exchange for the three dimensionalobject. Operation (b) can be performed in a time period that can be lessthan or equal to about 6 hours. Operation (b) can be performed in a timeperiod that can be less than or equal to about 1 hour. The pressure canbe at least about 10⁻³ Torr or more. The pressure can be at least about1 Torr or more. The pressure can be at least about 750 Torr or more.Operation (b) can be performed without iterative and/or correctiveprinting. The request can be received from the customer.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; an energy source that provides an energy beam tothe powder material in the powder bed; and a controller operativelycoupled to the energy source and programmed to (i) receive instructionsto generate the three-dimensional object according to a customerrequest, and (ii) within at most about 12 hours, direct the energy beamalong a predetermined path in accordance with the instructions totransform a portion of the powder material to a transformed materialthat hardens to form at least one layer of a hardened material as partof the three-dimensional object.

In another aspect, a method for printing a three dimensional objectcomprises (a) receiving a request for generation of a three dimensionalobject from a customer, wherein the three dimensional object comprisesan elemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; (b) additively generating the three dimensional object accordingto a model of the requested three dimensional object; and (c) deliveringthe three dimensional object to the customer, wherein the threedimensional object is generated without at least one of iterativeprinting and corrective printing.

Operation (b) can be performed without iterative and without correctiveprinting. Operation (b) can be performed at a pressure that is at leastabout 10⁻⁶ Torr or more. The three dimensional object can be additivelygenerated at a deviation from the model by at most about 50 micrometersor less. The method may further comprise transforming the design intoinstructions usable by the processor to additively generate the threedimensional object. The method may further comprise receiving an item ofvalue from the customer in exchange for the three dimensional object. Insome instances, in operation (b), the formation of the three dimensionalobject reaches completion without iterative and corrective printing. Therequest can be received from the customer.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to: (a) supply a layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the powdermaterial comprises an elemental metal, metal alloy, ceramic, or anallotrope of elemental carbon; and (b) direct an energy beam from anenergy source to the powder bed to transform at least a portion of thepowder material to a transformed material that subsequently hardens toyield the three-dimensional object that is generated without at leastone of iterative printing and corrective printing.

In another aspect, an apparatus for generating a three-dimensionalobject comprises (a) an enclosure that accommodates a powder bedcomprising the powder material comprising an elemental metal, metalalloy, ceramic, or an allotrope of elemental carbon; and (b) an energysource that provides an energy beam to the powder material in the powderbed to form at least a portion of a three-dimensional object, whereinupon formation the three-dimensional object is generated without atleast one of iterative printing and corrective printing.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; an energy source that provides an energy beam tothe powder material in the powder bed; and a controller operativelycoupled to the energy source and programmed to (i) receive instructionsto generate the three-dimensional object according to a customerrequest, and (ii), direct the energy beam along a predetermined path inaccordance with the instructions to transform a portion of the powdermaterial to a transformed material that hardens to form at least onelayer of a hardened material as part of the three-dimensional object,wherein the three dimensional object is generated without at least oneof iterative printing and corrective printing.

In another aspect, a method for generating a three dimensional objectcomprises (a) providing a layer of powder material comprising anelemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; (b) transforming at least a portion of the powder material inthe layer to form a transformed material; (c) hardening the transformedmaterial to form a hardened material that is at least a portion of thethree dimensional object; (d) optionally repeating operations (a)-(c);and (e) removing the generated three dimensional object from a remainderof the powder material that did not form the three dimensional object,in a time period of 30 minutes or less after a last hardening operation.

In some instances, during the method the three dimensional object can bedevoid of one or more auxiliary features. The one or more auxiliarysupport feature can comprise a scaffold that encloses the threedimensional object. The powder material can be devoid of two or moremetals that form a eutectic alloy. A remainder of the powder materialthat did not form the at least a part of the three dimensional object,can be devoid of a continuous structure extending over about 1millimeter or more. A handling temperature of the three dimensionalobject can be at most about 100° C. or less. The handling temperaturecan be at most about 80° C. or less.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates the powder bed, wherein thepowder bed comprises a powder material having a ceramic, or an allotropeof elemental carbon; an energy source that provides an energy beam tothe powder material in the powder bed; an object removal mechanism thatremoves the three dimensional object from a remainder of the powdermaterial that did not form the three dimensional object; and acontroller operatively coupled to the energy source and programmed to(i) receive instructions to generate the three-dimensional objectaccording to a customer request, (ii) direct the energy beam along apredetermined path in accordance with the instructions to transform aportion of the powder material to a transformed material that hardens toform at least one layer of a hardened material as part of thethree-dimensional object, and (iii) direct the object removal mechanismto remove the three dimensional object from the remainder within at mostabout 30 minutes from a generation of the three dimensional object.

The object removal system can comprise a blockable mesh. The objectremoval system can comprise a robotic arm. The object removal system cancomprise a conveyor. The object removal system can comprise a revolvingopening.

In another aspect, an apparatus for leveling a top surface of powdermaterial of a powder bed comprises an enclosure that accommodates thepowder bed comprising the powder material; an energy source thatprovides an energy beam to the powder material in the powder bed to format least a portion of a three-dimensional object, wherein uponformation, the at least the portion of the three-dimensional object issuspended in the powder bed; and a powder leveling member for levelingan the top surface of the powder bed, wherein the leveling member isdisposed above the powder bed, wherein during use, the powder levelingmember displaces at least a portion of the three dimensional object byless than or equal to 300 micrometers.

In another aspect, a method for generating a three-dimensional objectsuspended in a powder bed comprises (a) dispensing powder material intoan enclosure to provide the powder bed, wherein the powder materialcomprises an elemental metal, metal alloy, ceramic, or an allotrope ofelemental carbon; (b) generating the three-dimensional object from aportion of the powder material, wherein upon generation thethree-dimensional object is suspended in the powder bed; and (c) using aleveling member to level an exposed surface of the powder bed such thatthe three-dimensional object suspended in the powder bed is displaced byabout 300 micrometers or less.

The generating can comprise additively generating. The powder bed can bedevoid of a supporting scaffold substantially enclosing thethree-dimensional object. In some embodiments, in (c), thethree-dimensional object can be displaced by about 20 micrometers orless. The powder material can be devoid of at least two metals that arepresent at a ratio that forms a eutectic alloy. The powder material cancomprise at most a metal that can be substantially of a single elementalmetal composition. The powder material can comprise a metal alloy thatcan be of a single metal alloy composition. The three-dimensional objectcan be planar. The three-dimensional object can be a wire. Thethree-dimensional object can be devoid of auxiliary support features.The three-dimensional object can comprise auxiliary support featuresthat are suspended in the powder bed. The transforming can be conductedaccording to a model that can be representative of the three dimensionalobject. The leveling mechanism can comprise a roller. The levelingmechanism can comprise a rake. The leveling mechanism can besynchronized with a powder dispenser. The powder dispenser can comprisean air knife. The powder dispenser can comprise a curved tube with anopening through which the powder can be released. The powder dispensercan comprise an auger screw. The rake has a plurality of blades withvarying height. The rake has a plurality of blades with varying angle ofcontact on the additional layer of powder material. In some instances,at least a fraction of the powder in the powder layer can be removedfrom the substrate prior to (b). At times, at least a fraction of thepowder in the powder layer can be collected by a powder recyclingsystem. The fraction of the powder collected by the powder recyclingsystem can be re-circulated, and at least a fraction of the powdercollected by the powder recycling system can be dispensed in operation(c). The leveling mechanism can comprise a plurality of needlesdistributed across the axis of the leveling mechanism. The needles canbe arranged on the leveling mechanism such that each needle in theplurality of needles contacts a different location of the powder. Theplurality of needles can level a powder dispensed from a top-dispensepowder dispenser. The leveling mechanism can further comprise a rolleradjacent to the plurality of needles. The needles can be distributedacross the axis of the leveling mechanism. The leveling mechanism cancomprise a blade. The leveling mechanism can comprise a powder levelsensor configured to determine a powder level located ahead of theleveling mechanism. The powder level sensor can be an optical sensor.The powder level sensor can be in communication with a powder dispensingsystem configured to dispense powder when the powder level sensordetects a powder level below a predetermined threshold. The rake cancomprise a set of blades each of which can be diagonal with respect to asurface of the powder layer or of the additional layer. Dispensing ofpowder from the auger screw can be controlled by a valve. The rake cancomprise a smooth blade. The roller may flatten powder dispensed from apowder dispenser. The powder dispenser can comprise a top-dispensepowder dispenser. A surface of the roller has a static frictioncoefficient of at least about 0.5 or more. The roller may comprise anactive rotation mechanism configured to force rotation of the roller ina clockwise direction. The roller may comprise an active rotationmechanism configured to force rotation of the roller in acounter-clockwise direction. The roller may comprise an eccentric shapesuch that during rotation it allows for multi-height planarization. Theblade may level the powder dispensed from a top-dispense powderdispenser. The top-dispense mechanism can comprise of a vibrating meshthough which the powder is released to the powder bed. The vibration canbe driven by an ultrasonic transducer. The vibration can be driven by apiezo-electric device. The vibration can be driven by a rotating motorwith an eccentric cam.

In another aspect, a system for generating a three-dimensional objectsuspended in a powder bed comprises an enclosure that accommodates thepowder bed, wherein the powder bed comprises powder material having anelemental metal, metal alloy, ceramic, or an allotrope of elementalcarbon; a leveling member that levels an exposed surface of the powderbed; and a controller operatively coupled to the energy source and theleveling member and programmed to (i) receive instructions to generatethe three-dimensional object, (ii) generate the three-dimensional objectfrom a portion of the powder material in accordance with theinstructions, wherein upon generation the three-dimensional object issuspended in the powder bed, and (iii) direct the leveling member tolevel the exposed surface of the powder bed such that thethree-dimensional object suspended in the powder bed is displaced byabout 300 micrometers or less.

In some embodiments, upon generation of the three-dimensional object,the powder bed can be devoid of a supporting scaffold substantiallyenclosing the three-dimensional object. The system may further comprisea powder dispenser that provides the powder material into the enclosure.The leveling mechanism can be coupled to the powder dispenser. Thepowder dispenser can be disposed adjacent to the powder bed, and whereinthe powder dispenser has an exit opening that can be located at adifferent location than a bottom portion of the powder dispenser thatfaces the powder bed. The exit opening can be located at a side of thepowder dispenser. The side can be a portion of the powder dispenser thatdoes not face the powder bed or does not face a direction opposite tothe powder bed. The exit opening can comprise a mesh. The controller canbe operatively coupled to the powder dispenser and programmed to controlan amount of the powder material that can be dispensed by the powderdispenser into the enclosure. The controller can be operatively coupledto the powder dispenser and programmed to control a position of thepowder dispenser. The powder dispenser can be movable. The system mayfurther comprise one or more mechanical members operatively coupled tothe powder dispenser, wherein the one or more mechanical members subjectthe powder dispenser to vibration. The controller can be operativelycoupled to the one or more mechanical members. The controller can beprogrammed to control the one or more mechanical members to regulate anamount of the powder material that can be dispensed by the powderdispenser into the enclosure. The controller can be programmed tocontrol a position of the leveling member, wherein the leveling membercan be movable. The controller can be programmed to control a force orpressure exerted by the leveling member on the powder material. Theleveling member can comprise a removal unit that removes excess powdermaterial from the powder bed. The removal unit may comprise a source ofvacuum, magnetic force, electric force, or electrostatic force. Theremoval unit can comprise a reservoir for accommodating an excess ofpowder material. The removal unit can comprise one or more sources ofnegative pressure for removing an excess of powder material from thepowder bed. The controller can be programmed to direct removal of anexcess of powder material using the removal unit. The leveling membercan comprise a knife.

In another aspect, an apparatus for removing a generating athree-dimensional object comprises (a) an enclosure that accommodates apowder bed comprising powder material having elemental metal, metalalloy, ceramics, or an allotrope of elemental carbon, wherein duringuse, at least a portion of the powder material is transformed in to atransformed material that subsequently hardens to form thethree-dimensional object; and (b) a base that is situated within theenclosure, wherein during use the powder material is situated adjacentto the base, and wherein the base comprises a mesh that is operable inat least blocked and unblocked positions such that (i) when blocked, themesh does not permit either the powder material or the three-dimensionalobject to pass though the mesh, and (ii) when unblocked, the meshpermits at least part of the powder material to pass though the mesh andprevents the three-dimensional object from passing though the mesh.

In another aspect, an apparatus for generating a three dimensionalobject comprises an enclosure containing a powder material comprisingelemental metal, metal alloy, ceramics, or an allotrope of elementalcarbon; and a base disposed within the enclosure; wherein the powdermaterial is disposed adjacent to the base, wherein the base comprises ablockable mesh that when unblocked, the mesh is of a type that bothpermits at least part of the powder material to flow though, andprevents the three dimensional object from flowing though. In someembodiments, unblocked can comprise altering the position (e.g.,vertical or horizontal position) of the base. In some embodiments,unblocked does not comprise altering the position of the base.

In another aspect, a system for generating a three-dimensional objectcomprises an enclosure that accommodates a powder bed, wherein thepowder bed comprises a powder material comprising an elemental metal,metal alloy, ceramic, or an allotrope of elemental carbon; an energysource that provides an energy beam to the powder material in the powderbed; a base disposed adjacent to the powder bed, wherein the basecomprises a blockable mesh that is alternately blocked or unblocked,wherein (i) when the blockable mesh is blocked, the powder material doesnot flow through the mesh, and (ii) when the blockable mesh isunblocked, at least part of the powder material flows though the meshwhile the three-dimensional object is prevented from flowing though themesh; and a controller operatively coupled to the energy source andprogrammed to (i) receive instructions to generate at least a portion ofthe three-dimensional object, (ii) direct the energy beam along a pathin accordance with the instructions to transform a portion of the powdermaterial to a transformed material that hardens to form at least onelayer of a hardened material as part of the three-dimensional object,and (iii) directs the mesh blocking device to unblock the mesh. Theblockable mesh can be unblocked by altering a position of the blockablemesh or a mesh blocking device adjacent to the blockable mesh. The meshblocking device can be a movable plane that alternates between avertical or horizontal position that blocks the blockable mesh andanother vertical or horizontal position that unblocks the blockablemesh. The base can alternate between a vertical or horizontal positionthat blocks the blockable mesh and another vertical or horizontalposition that unblocks the blockable mesh.

In another aspect, a method for generating a three dimensional objectcomprises (a) dispensing a layer of powder material adjacent to a base,wherein the base comprises a mesh that permits at least a portion of thepowder to flow through when the mesh is unblocked; (b) transforming aportion of the powder material to a transformed material; (c) hardeningthe transformed material to provide a hardened material that is at leasta portion of the three-dimensional object; and (d) unblocking the meshto retrieve the hardened material from a remainder of the powdermaterial that does not form the at least the portion of thethree-dimensional object.

Upon retrieving the hardened material, the hardened material may rest ona substrate that is disposed below the base. Upon retrieving thehardened material, the remainder may be removed from the hardenedmaterial. The unblocking may comprise moving the mesh relative to thepowder material. The unblocking may comprise moving the mesh relative tothe base. A surface of the mesh may be moved relative to the powdermaterial by pulling on one or more posts connected to the surface. Theone or more posts may be removable from an edge of the base by athreaded connection. In some embodiments, the hardening comprisesdirecting cooling gas to the transformed material to cool thetransformed material and yield the hardened material.

In another aspect, a method for generating a three-dimensional objectsuspended in a powder bed comprises (a) dispensing powder material intoan enclosure to provide a powder bed, wherein the powder bed comprises atop surface; (b) generating the three-dimensional object from a portionof the powder material by transforming the powder material into atransformed material that subsequently forms a hardened material,wherein the hardened material protrudes from the top surface of thepowder bed, wherein the hardened material is movable within the powderbed; and (c) adding a layer of powder material on the top surface of thepowder bed, wherein the adding displaces the hardened material by about300 micrometers or less, wherein the top surface of the layer of powdermaterial is substantially planar.

In another aspect, a method for generating a three dimensional objectfrom a powder material comprises (a) dispensing powder material into anenclosure to provide a powder bed, wherein the powder bed comprises atop surface; (b) using an energy beam from an energy source,transforming the powder material into a transformed material thatsubsequently forms a hardened material, wherein the hardened materialprotrudes from the top surface of the powder bed, and wherein thehardened material is movable within the powder bed; and (c) dispensing alayer of powder material on the top surface of the powder bed such thatthe hardened material is displaced by about 300 micrometers or less,wherein upon dispensing the layer of powder material, the top surface ofthe powder bed is substantially planar.

The hardened material can be at least a portion of the three-dimensionalobject. The at least the portion of the three-dimensional object cancomprise warping, buckling, bulging, curling, bending, rolling, orballing. The dispensing in (c) can further comprise using a powderdispensing member to deposit the layer of powder material on the topsurface of the powder bed. The dispensing in (c) can further compriseusing a powder leveling member to level the top surface of powder bed byshearing an excess of the powder material. The dispensing in (c) canfurther comprise using a powder removal member to remove an excess ofpowder material without contacting the layer of powder material. Thethree-dimensional object can be suspended in the powder bed. Thethree-dimensional object can be devoid of auxiliary support features.The auxiliary support features comprise a scaffold that substantiallyencloses the three-dimensional object. The three-dimensional object cancomprise auxiliary support features that are suspended in the powderbed. The powder material can be devoid of at least two metals that arepresent at a ratio that forms a eutectic alloy. The leveling can beconducted after the powder dispensing mechanism completed dispensing arow of powder material in the enclosure. The leveling can be conductedafter the powder dispensing mechanism completed dispensing a portion ofa layer of powder material in the enclosure. The leveling can beconducted after the powder dispensing mechanism completed dispensing alayer of powder material in the enclosure. The powder dispensingmechanism can span at least part of the enclosure length. The powderdispensing mechanism can span an entire length of the enclosure. Thepowder dispensing mechanism can span at least part of the enclosurewidth. The powder dispensing mechanism can span an entire width of theenclosure. The powder dispensing mechanism can comprise a mesh throughwhich the powder material can be able to dispense out of the dispensingmechanism. The powder dispensing mechanism can comprise a position ofthe mesh that prevents the powder material held within the powderdispensing mechanism to be dispensed out of the powder dispensingmechanism though the mesh. The powder dispensing mechanism can comprisea position of the mesh that allows the powder material held within thepowder dispensing mechanism to be dispensed from the powder dispensingmechanism though the mesh. The position of the mesh may determine theamount of powder material dispensed from the powder dispensing mechanismthrough the mesh. The powder dispensing mechanism can comprise a firstposition of the mesh that prevents the powder material held within thepowder dispensing mechanism to be dispensed out of the powder dispensingmechanism though the mesh, and a second position of the mesh that allowsthe powder material held within the powder dispensing mechanism to bedispensed from the powder dispensing mechanism though the mesh. The rateat which the powder dispensing mechanism alternates between the firstand second position may alter at least one dispensing parameter of thepowder material. The dispensing parameter can comprise homogeneity ofpowder distribution in the enclosure. The dispensing parameter cancomprise amount of powder dispensed from the mesh. The rate at which theamount of time the mesh can be at in a first or in a second position maydetermine the amount of powder material dispensed from the powderdispensing mechanism. The rate at which the mesh alternates between thefirst and the second position may determine the area covered by thepowder material dispensed from the powder dispensing mechanism in theenclosure. The powder dispensing mechanism can further comprise acontrol mechanism coupled to the powder dispensing mechanism. Thecontrol mechanism may regulate the amount of powder dispensed. Thecontrol mechanism may control the position of the powder dispensingmechanism. The control can be automatic or manual. The control mechanismmay control the position of the mesh. The control mechanism can comprisea sensor sensing the amount of powder material dispensed by thedispensing mechanism. The control mechanism can comprise a sensorsensing the amount of powder material accumulated in the enclosure. Thecontrol mechanism can comprise a sensor sensing the amount of powdermaterial accumulated in a position in the enclosure. The leveling can beconducted by a leveling mechanism. The leveling mechanism can comprise aleveling aid comprising a rolling cylinder, a rake, a brush, a knife, ora spatula. The movement of the leveling aid can comprise forwardmovement, backward movement, sideward movement or movement at an angle.The movement of the leveling aid can comprise a lateral movement. Theleveling mechanism can span at least part of the enclosure length. Theleveling mechanism can span an entire length of the enclosure. Theleveling mechanism can span at least part of the enclosure width. Theleveling mechanism can span an entire width of the enclosure. Theleveling mechanism can further comprise a control mechanism coupled tothe leveling aid. The control mechanism can comprise a sensor sensingthe level of the powder material in the enclosure. The leveling aid cancomprise a rolling cylinder. The rolling cylinder may rotate clockwiseor anti clockwise in a position perpendicular to the long axis of thecylinder. The rolling cylinder may rotate with the direction of lateralmovement of the leveling aid or opposite to the lateral movement of theleveling aid. The dispensing can comprise vibrating at least part of thepowder material in the powder dispensing mechanism. The dispensing cancomprise vibrating at least part of an opening through which the powdermaterial exits the powder dispensing mechanism. The leveling maydisplace an object within or under the deposited layer of powdermaterial by at most 20 micrometers. The displacement can be a horizontaldisplacement. Leveling may comprise utilizing a blade. The levelingmechanism may level the layer of powder material while moving in a firstdirection. Leveling can comprise moving the blade in the firstdirection. Leveling can comprise moving the blade in a directionopposite to the first direction.

In another aspect, a system for generating a three dimensional objectcomprises an enclosure that accommodates a powder bed comprising powdermaterial, wherein the powder bed comprises a top surface; an energysource that provides an energy beam to the powder material in the powderbed; a layer dispensing mechanism that provides the powder material inthe enclosure or on the top surface of the powder bed; and a controlleroperatively coupled to the energy source and the layer dispensingmechanism and programmed to (i) receive instructions to generate thethree-dimensional object, (ii) in accordance with the instructions, usethe energy beam to transform the powder material into a transformedmaterial that subsequently forms a hardened material, wherein thehardened material protrudes from the top surface of the powder bed, andwherein the hardened material is movable within the powder bed, and(iii) direct the layer dispensing mechanism to dispense a layer ofpowder material on the top surface of the powder bed such that thehardened material is displaced by about 300 micrometers or less, whereinthe top surface of the dispensed layer of powder material issubstantially planar.

The hardened material can be at least a portion of the three-dimensionalobject. The layer dispensing mechanism can comprise a powder dispensingmember that provides the powder material. The controller can beoperatively coupled to the powder dispensing member and programmed todirect the powder dispensing member to dispense the layer of powdermaterial on the top surface of the powder bed on in the enclosure. Thelayer dispensing mechanism can comprise a powder leveling member thatlevels the top surface of the powder bed without contacting the topsurface of the powder bed. The controller can be operatively coupled tothe powder leveling member and programmed to direct the powder levelingmember to level the top surface of the powder bed. The powder levelingmember may shear an excess of the powder material from the top surfaceof the powder bed. The powder leveling member may level the top surfaceof the powder bed without displacing the excess of powder material toanother position in the powder bed. The powder leveling member cancomprise a knife that shears an excess of powder material. The layerdispensing mechanism can comprise a powder removal member that removesan excess of powder material from the top surface of the powder bedwithout contacting the top surface of the powder bed. The controller canbe operatively coupled to the powder removal member and programmed todirect the powder removal member to remove the excess of powder materialfrom the top surface. The powder removal member can comprise a source ofvacuum, a magnetic force generator, an electrostatic force generator, anelectric force generator, or a physical force generator. The powderleveling member can be coupled to the powder removal member. The powderremoval member can be coupled to a powder dispensing member. The excessof powder material can be reusable by the powder dispensing member. Thepowder dispensing member can be disposed adjacent to the powder bed. Thepowder dispensing member can comprise an exit opening that can belocated at a location that can be different from the bottom of thepowder dispensing member that faces the top surface of the powder bed.The exit opening can be located at a side portion of the powderdispensing mechanism. The side can be a portion of the powder dispensingmechanism may be one that either does not face the top surface of thepowder bed, or does not face a direction opposite to the top surface ofthe powder bed. The controller may regulate an amount of the powdermaterial that can be dispensed by the powder dispensing member. Thesystem may further comprise one or more mechanical members operativelycoupled to the powder dispensing member. The one or more mechanicalmembers may subject the powder dispensing member to vibration. Thecontroller can be operatively coupled to the one or more mechanicalmembers. The controller can be programmed to control the one or moremechanical members to regulate an amount of the powder material that canbe dispensed by the powder dispensing member into the enclosure. Thepowder dispensing member can be located adjacent to the top surface ofthe powder bed and can be separated from the top surface of the powderbed by a gap. The powder dispensing member can comprise a gas-flow. Thepowder dispensing member can comprise an airflow. The powder dispensingmember can comprise a vibrator. The controller can be operativelycoupled to the vibrator and regulate the vibrator. The controller mayregulate the vibration amplitude of the vibrator. The controller mayregulate the vibration frequency of the vibrator. The controller mayregulate the amount of material released by the powder dispensingmember. The controller may regulate the rate of powder dispensed by thepowder dispensing member. The controller may regulate the velocity ofpowder dispensed by the powder dispensing member. The controller mayregulate the position of the powder dispensing member. The position canbe a vertical position. The position can be a horizontal position. Thecontroller may regulate the position of the layer dispensing mechanism.The position can be a vertical position. The position can be ahorizontal position. The controller may regulate the height of thepowder layer formed by the layer dispensing mechanism. The levelingmember can further comprise a blade. The controller can be operativelycoupled to the blade and may regulate the rate of movement of the blade.The controller can be operatively coupled to the blade and may regulatethe position of the blade. The position can be a vertical position. Theposition can be a horizontal position.

In another aspect, an apparatus for leveling a top surface of powdermaterial of a powder bed comprises an enclosure that accommodates thepowder bed comprising the powder material; an energy source thatprovides an energy beam to the powder material in the powder bed to format least a portion of a three-dimensional object that is movable in thepowder bed; and a layer dispensing mechanism for dispensing a layer ofpowder material that is substantially planar, wherein during use, thelayer dispensing mechanism displaces at least a portion of the threedimensional object by less than or equal to 300 micrometers.

In another aspect, an apparatus for leveling a powder material for theformation of a three dimensional object comprises (a) a powder levelingmember that shears an excess of powder material in a powder bed in whichthe three-dimensional object is generated; and (b) a powder removingmember that removes the excess of powder material, wherein the powderremoving member is coupled to the powder leveling member; wherein theleveling mechanism is able to displace the three-dimensional object byat most 300 micrometers.

The three dimensional object can be suspended in the powder material.The powder material can be devoid of a continuous structure extendingover about 1 millimeter or more. The powder material can be devoid of ascaffold enclosing the three dimensional object. The powder material canbe devoid of two or more metals at a ratio that can form at least oneeutectic alloy. The leveling mechanism can be able to displace an objectthat can be suspended in the powder material by at most 20 micrometers.The apparatus may further comprise a moving member (e.g., a displacingmember) coupled to at least one of the powder leveling member and thepowder removing member. The translation member may translate the powderdispenser along a horizontal path that can comprise at least a portionof the horizontal cross-section of the powder bed. The levelingmechanism can be connected to a powder dispensing member that dispensesthe powder material into an enclosure. The three dimensional object canbe devoid of auxiliary supports. The object can comprise auxiliarysupports.

In another aspect, an apparatus for dispensing a powder material for theformation of a three dimensional object comprises (a) a powder reservoirthat accommodates a powder material; (b) an exit opening through whichthe powder material can exit the apparatus to the powder bed, whereinthe apparatus facilitates a free fall of the powder material usinggravitational force, wherein the apparatus is suspended above the powderbed and is separated from the exposed surface of the powder bed by agap, wherein the exit opening is situated on a face of the apparatusthat is different from a bottom of the apparatus; (c) a translationmember coupled to the reservoir, wherein the translation membertranslated the powder dispenser along a horizontal and/or vertical path,wherein the horizontal path comprises a path within a horizontal crosssection of the powder bed, wherein the vertical path comprises a pathwithin the gap; and (d) an obstruction situated within the exit opening,wherein the obstruction regulates the amount of powder dispensed thoughthe exit opening.

The exit opening can be situated on a side of the apparatus. Theapparatus can be of a shape other than a sphere. The shape of theapparatus can be other than an ellipsoid. The bottom of the apparatuscan comprise a first slanted bottom plane of the apparatus that facesthe substrate. The first slanted bottom plane forms a first acute anglewith a plane parallel to the average surface of the substrate, in afirst direction. In some embodiments, any additional slanted bottomplane of the apparatus may form a second acute angle with a planeparallel to the average surface of the substrate, in the firstdirection. The first slanted bottom plane may form a first acute anglewith a plane parallel to the average surface of the substrate, in afirst direction. In some embodiments, any optional additional slantedbottom plane of the apparatus forms a second acute angle with a planeparallel to the average surface of the substrate, in a directionopposite to first direction. The additional slanted bottom plane can beseparated from the exit opening by a gap. The gap can be a vertical gap.The gap can be a horizontal gap. The gap can be both a vertical and ahorizontal gap. The obstruction can comprise a mesh. The mesh cancomprise a hole that allows the powder material within the apparatus toexit the apparatus. The hole in the mesh may have a fundamental lengthscale from at least about fifty (50) micrometers to at most about one(1) millimeters. The powder material can comprise particles of averagefundamental length scale from at least about 25 micrometers to at mostabout 45 micrometers. The obstruction can comprise a blade. Theobstruction can comprise both a blade and a mesh. The blade can be adoctor blade. The apparatus can comprise a vibrator. The apparatus cancomprise an array of vibrators. The array of vibrators may be arrangedin a linear pattern. The array of vibrators may be arranged along aline. The array of vibrators may be arranged along the opening. Thevibrator can comprise a motor. The powder material may exit theapparatus on operation of the vibrator. The vibrator may generatevibrations with a frequency of at least about 200 Hertz. The vibratormay generate vibrations with an amplitude of at least about 7 times thegravitational force (G). The apparatus may be able to travel in ahorizontal direction from one side of the powder bed to the other sideof the powder bed. The apparatus can further comprise a leveling member.The apparatus can be connected to the leveling member. The levelingmember can comprise a blade. The blade can comprise a concave plane. Theblade can comprise a tapered bottom plane. The tapered bottom planeforms an acute angle with the average top surface of the powdermaterial. The blade can comprise a compliant mounting. The compliantmounting allows the blade to move vertically. The compliant mountingallows the blade to move vertically when confronting an object. Thecompliant mounting allows the blade to move vertically when confrontingat least part of the three dimensional object. The concave plane can beutilized in leveling a layer of powder material deposited adjacent tothe substrate. The concave plane may face the substrate. The concaveplane can be slanted. The vertical position of the apparatus can beadjustable. The vertical position of the blade can be adjustable. Theapparatus may further comprise a bulk reservoir capable of containingthe powder material.

In another aspect, a method for generating a three-dimensional objectcomprises (a) dispensing a layer of powder material to provide a powderbed using a powder dispensing mechanism comprising: (i) a powderreservoir that accommodates a powder material; (ii) an exit openingthrough which the powder material can exit the apparatus to the powderbed, wherein the apparatus facilitates a free fall of the powdermaterial using gravitational force, wherein the apparatus is suspendedabove the powder bed and is separated from the exposed surface of thepowder bed by a gap wherein the exit opening is situated on a face ofthe apparatus that is different from a bottom of the apparatus; (iii) atranslation member coupled to the reservoir, wherein the translationmember translated the powder dispenser along a horizontal and/orvertical path, wherein the horizontal path comprises a path within ahorizontal cross section of the powder bed, wherein the vertical pathcomprises a path within the gap; and (iv) an obstruction situated withinthe exit opening, wherein the obstruction regulates the amount of powderdispensed though the exit opening; (b) leveling the exposed surface ofthe powder bed; and (c) generating at least a portion of thethree-dimensional object from at least a portion of the powder material.

In another aspect, a system for generating a three dimensional objectcomprises an enclosure that accommodates a powder bed; (a) an energysource that provides an energy beam to the powder material, and therebytransforms the powder material into a transformed material thatsubsequently hardens to form a hardened material, wherein the hardenedmaterial may form at least a part of the three-dimensional object; apowder dispensing member that dispenses the powder material into thepowder bed, comprising: (i) a powder reservoir that accommodates apowder material; (ii) an exit opening through which the powder materialcan exit the apparatus to the powder bed, wherein the apparatusfacilitates a free fall of the powder material using gravitationalforce, wherein the apparatus is suspended above the powder bed and isseparated from the exposed surface of the powder bed by a gap whereinthe exit opening is situated on a face of the apparatus that isdifferent from a bottom of the apparatus; (iii) a translation membercoupled to the reservoir, wherein the translation member translated thepowder dispenser along a horizontal and/or vertical path, wherein thehorizontal path comprises a path within a horizontal cross section ofthe powder bed, wherein the vertical path comprises a path within thegap; and (iv) an obstruction situated within the exit opening, whereinthe obstruction regulates the amount of powder dispensed though the exitopening; (b) a powder leveling member that levels an exposed surface ofthe powder bed; and (c) a controller operatively coupled to the energysource, the powder dispensing member, the powder leveling member, andthe powder removing member, and is programmed to: (i) direct the powderdispenser to dispense a first layer of the powder material having afirst top surface into the powder bed, (ii) receive instructions togenerate at least part of the three-dimensional object, (iii) generatethe at least part of the three-dimensional object from a portion of thepowder material in accordance with the instructions, (iv) direct thepowder dispenser to dispense a second layer of powder material having asecond top surface adjacent to the first top surface, and (v) direct thepowder leveling member to level the second top surface to a first planarsurface that is at or below the lowest point of the second top surface.

In another aspect, a method for generating a three-dimensional objectcomprises (a) dispensing a first layer of powder material in anenclosure to provide a powder bed having a first top surface; (b)directing an energy beam to the first layer of powder material togenerate at least a portion of the three-dimensional object from atleast a portion of the first layer; (c) subsequent to generating atleast the portion of the three-dimensional object, dispensing a secondlayer of powder material in the enclosure, wherein the second layer ofpowder material comprises a second top surface; (d) shearing the secondlayer of powder material to form a first planar surface, wherein thefirst planar surface is at or below a lowest point of the second topsurface; and (e) removing substantially all powder material that isabove a second planar surface from the second layer of powder material,wherein the second planar surface is located below the first planarsurface, and wherein the removing occurs in the absence of contactingthe powder bed.

The generating can comprise transforming the powder material to generatea transformed material that subsequently hardens to form a hardenedmaterial, wherein at least a portion of the hardened material protrudesfrom the first top surface, thus forming a protrusion. The protrusioncan be at least a portion of the three-dimensional object. Theprotrusion can comprise warping, bending, bulging, rolling, curling, orballing of the hardened material. The protrusion can comprise a hardenedmaterial that can be not a part of the three-dimensional object. Theprotrusion may have a height from about 10 micrometers to about 500micrometers with respect to the first top surface. In some embodiments,an average vertical distance from the first top surface to the secondplanar surface can be from about 5 micrometers to about 1000micrometers. The average vertical distance from the first top surface tothe first planar surface can be from about 10 micrometers to about 500micrometers. The removing can comprise using vacuum suction, magneticforce, electrostatic force, electric force, or physical force. In someexamples, the removing can comprise vacuum suction. The method mayfurther comprise reusing an excess of powder material from the firstlayer and/or second layer. The second planar surface can be situatedabove the first top surface. The first layer of powder material can bedispensed using gravitational force. The first layer of powder materialcan be dispensed using gas-flow that displaces the powder material. Theairflow travels at a velocity having a Mach number from about 0.001 toabout 1. In some embodiments, upon shearing the second layer of powdermaterial to form the first planar surface, the at least the portion ofthe three-dimensional object can be displaced by about 300 micrometersor less.

In another aspect, a system for generating a three dimensional objectcomprises an enclosure that accommodates a powder bed comprising powdermaterial; an energy source that provides an energy beam to the powdermaterial in the powder bed; a powder dispensing member that dispensesthe powder material into the enclosure to provide the powder bed; apowder leveling member that levels a top surface of the powder bed; apowder removing member that removes powder material from the top surfaceof the powder bed without contacting the top surface; and a controlleroperatively coupled to the energy source, the powder dispensing member,the powder leveling member, and the powder removing member, wherein thecontroller is programmed to: (i) direct the powder dispensing member todispense a first layer of the powder material in the enclosure toprovide the powder bed having a first top surface, (ii) direct theenergy beam from the energy source to the first layer of powder materialto generate at least a portion of the three-dimensional object from aportion of the first layer, (iii) direct the powder dispensing member todispense a second layer of powder material in the enclosure, wherein thesecond layer of powder material comprises a second top surface, (iv)direct the powder leveling member to shear the second layer of powdermaterial to form a first planar surface, wherein the first planarsurface is at or below a lowest point of the second top surface, and (v)direct the powder removing member to remove substantially all powdermaterial that is above a second planar surface from the second layer ofpowder material, wherein the second planar surface is located below thefirst planar surface.

The energy source can provide an energy beam to the powder material andthereby transforms the powder material into a transformed material thatsubsequently hardens to form a hardened material, wherein the hardenedmaterial may form at least a part of the three-dimensional object. Thesecond planar surface can be disposed above the first top surface. Insome embodiments, upon the powder leveling member shearing the secondlayer of powder material to form the first planar surface, the at leasta portion of the three-dimensional object is displaced by about 300micrometers or less. The powder dispensing member can be separated fromthe exposed surface of the powder bed by a gap. The gap may have aseparation distance (e.g., vertical separation distance) that can befrom about 10 micrometers to about 50 millimeters. In some embodiments,as the powder material exits the powder dispensing member to anenvironment of the enclosure and travels in the direction of the powderbed, it encounters at least one obstruction. In some examples, duringoperation, the powder dispensing member can be in (e.g., fluid)communication with the powder bed along a path that includes at leastone obstruction. The obstruction can comprise a rough surface. Theobstruction can comprise a slanted surface that forms an angle with thetop surface of the powder bed. The powder removing member can beintegrated with the powder dispensing member as a powderdispensing-removing member. The powder dispensing-removing member cancomprise one or more powder exit ports and one or more vacuum entryports. The powder dispensing-removing member can comprise one or morepowder exits and one or more vacuum entries. The powderdispensing-removing member can comprise one or more powder exit portsand one or more vacuum entry ports are alternatingly arranged. Thepowder dispensing-removing member can comprise one or more powder exitsand one or more vacuum entries that operate sequentially. The powderremoving member can comprise a vacuum nozzle.

In another aspect, an apparatus for forming a three-dimensional objectcomprises a controller that is programmed to (a) supply a first layer ofpowder material from a powder dispensing member to a powder bedoperatively coupled to the powder dispensing member, wherein the firstlayer comprises a first top surface; (b) direct an energy beam from anenergy source to the powder bed to transform at least a portion of thepowder material to a transformed material that subsequently hardens toyield at least a portion of the three-dimensional object; (c) subsequentto yielding at least the portion of the three-dimensional object, supplya second layer of powder material from the powder dispensing member tothe powder bed operatively coupled to the powder dispensing member,wherein the second layer of powder material comprises a second topsurface; (d) direct a powder removal member operatively coupled to thepowder leveling member to remove substantially all powder material thatis above a second planar surface from the second layer of powdermaterial, wherein the second planar surface is located below the firstplanar surface, and wherein the removing occurs in the absence ofcontacting the powder bed.

In another aspect, an apparatus for generating a three dimensionalobject comprises (a) a powder bed comprising powder material; (b) powderdispenser that dispenses a predetermined amount of powder material at aposition in the powder bed, wherein the powder dispenser is disposedabove the powder bed and is separated from the powder bed by a gap; and(c) a leveling mechanism configured to level the powder material in thepowder bed without relocating the excess amount of powder material ontoa different position in the powder bed, wherein the leveling mechanismis located above the powder bed and laterally adjacent to the powderdispenser.

The leveling mechanism can comprise a knife. The leveling mechanism cancomprise a knife that performs the shearing. The leveling mechanism cancomprise a suction device that sucks the excess of powder material. Theleveling mechanism can comprise a device for collecting the excess ofpowder material. The leveling mechanism can comprise a device forremoving the excess of powder material from the powder bed.

In another aspect, an apparatus for forming a three-dimensional object,comprises a controller that is programmed to (a) supply a first layer ofpowder material from a powder dispensing mechanism to a powder bedoperatively coupled to the powder dispensing member; (b) direct anenergy beam from an energy source to the powder bed to transform atleast a portion of the powder material to a transformed material thatsubsequently hardens to yield the three-dimensional object; (c) supply asecond layer of powder material from the powder dispensing member to thepowder bed, wherein the second layer is disposed adjacent to the firstlayer; and (d) direct a powder leveling mechanism operatively coupled tothe powder dispensing member to level the exposed surface of the powderbed, wherein the leveling comprises removing an excess of the powdermaterial without relocating the excess amount of powder material onto adifferent position in the powder bed.

In another aspect, a method for generating a three-dimensional objectcomprises (a) providing a first layer of powder material into anenclosure to provide a powder bed; (b) generating at least a portion ofthe three-dimensional object from at least a portion of the powdermaterial; (c) dispensing a second layer of powder material onto thepowder bed, wherein the second layer of powder material comprises anexposed surface; and (d) leveling the exposed surface, wherein theleveling comprises removing an excess of the powder material withoutrelocating the excess amount of powder material onto a differentposition in the powder bed.

In another aspect, a system for generating a three dimensional object,comprising an enclosure that accommodates a powder bed; an energy sourcethat provides an energy beam to the powder material, and therebytransforms the powder material into a transformed material thatsubsequently hardens to form a hardened material, wherein the hardenedmaterial may form at least a part of the three-dimensional object; apowder dispensing member that dispenses the powder material into thepowder bed; a powder leveling member that levels an exposed surface ofthe powder bed without relocating the excess amount of powder materialonto a different position in the powder bed; and a controlleroperatively coupled to the energy source, the powder dispensing member,the powder leveling member, and the powder removing member, and isprogrammed to: (i) direct the powder dispenser to dispense a first layerof the powder material into the powder bed, (ii) receive instructions togenerate at least part of the three-dimensional object, (iii) generatethe at least part of the three-dimensional object from a portion of thepowder material in accordance with the instructions, (iv) direct thepowder dispenser to dispense a second layer of powder material having anexposed surface, and (v) direct the powder leveling member to level theexposed surface.

Additional aspects and advantages of the present disclosure will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein only illustrative embodiments of thepresent disclosure are shown and described. As will be realized, thepresent disclosure is capable of other and different embodiments, andits several details are capable of modifications in various obviousrespects, all without departing from the disclosure. Accordingly, thedrawings and description are to be regarded as illustrative in nature,and not as restrictive.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings or figures (also “FIG.” and “FIGS.” herein), ofwhich:

FIG. 1 illustrates a schematic of a three-dimensional (3D) printingsystem and its components;

FIG. 2 illustrates a schematic of the cooling member provided in the 3Dprinting system;

FIG. 3 illustrates a detailed view of the formation of a singlesolidified layer in the 3D printing process;

FIG. 4 shows a graph of a temperature time history of a powder layer orgroup of powder layers;

FIG. 5 schematically illustrates the volume of the powder bed heated bythe primary and complementary energy sources;

FIG. 6 illustrates a timeline of the 3D printing process for a singlelayer;

FIG. 7 illustrates a flow chart describing a 3D printing process;

FIG. 8 schematically illustrates a computer control system that isprogrammed or otherwise configured to facilitate the formation of a 3Dobject;

FIG. 9 depicts a schematic of select components of a three dimensional(3D) printing system which may be used to maintain planar uniformity ofa powder layer;

FIG. 10A schematically depicts an air knife for depositing powder onto asubstrate; FIG. 10B schematically depicts a curved tube for depositingpowder onto the substrate;

FIG. 11 depicts a rake for pushing, spreading and/or leveling powderalong a substrate without disturbing a 3D object in the powder;

FIGS. 12A-12F schematically depict vertical side cross sections ofvarious mechanisms for spreading and/or leveling the powder material;

FIGS. 13A-13D schematically depict vertical side cross sections ofvarious mechanisms for dispensing the powder material;

FIGS. 14A-14D schematically depict vertical side cross sections ofvarious mechanisms for spreading and leveling the powder material;

FIG. 15 schematically depicts vertical side cross sections of a levelingmechanism and a powder dispenser;

FIGS. 16A-16D schematically depict vertical side cross sections ofvarious mechanisms for dispensing the powder material;

FIG. 17 schematically depicts vertical side cross sections of variousmechanisms for dispensing the powder material;

FIGS. 18A-18D schematically depict vertical side cross sections ofvarious mechanisms for dispensing the powder material;

FIGS. 19A-19D schematically depict vertical side cross sections ofvarious mechanisms for dispensing the powder material;

FIG. 20 schematically depicts vertical side cross sections of a knifehaving a tapered bottom;

FIG. 21A depicts exposed metal planes within a layer of powder materialbefore leveling of the layer of powder material; FIG. 21B depictsexposed metal planes within a layer of powder material after leveling ofthe layer of powder material that was deposited on the planes in FIG.21A, using a leveling mechanism described herein;

FIG. 22 schematically depicts a vertical side cross sections of a rolldescribed herein;

FIG. 23 schematically depicts a vertical side cross sections of a powderremoval system (e.g., a suction device) described herein;

FIG. 24 schematically depicts vertical side cross sections of amechanism for spreading and leveling and removing the powder material;

FIGS. 25A-25C schematically depict bottom views of various mechanismsfor removing the powder material;

FIGS. 26A-26D schematically depict sequential stages in a method fordispensing and leveling a layer of powder material;

FIGS. 27A-27D schematically depict vertical side cross sections ofvarious powder dispensing members described herein; and

FIG. 28 schematically depicts vertical side cross sections of a powderdispensing member described herein.

The figures and components therein may not be drawn to scale. Variouscomponents of the figures described herein may not be drawn to scale.

DETAILED DESCRIPTION

While various embodiments of the invention have been shown and describedherein, it will be obvious to those skilled in the art that suchembodiments are provided by way of example only. Numerous variations,changes, and substitutions may occur to those skilled in the art withoutdeparting from the invention. It should be understood that variousalternatives to the embodiments of the invention described herein may beemployed.

Three-dimensional printing (also “3D printing”) generally refers to aprocess for generating a 3D object. For example, 3D printing may referto sequential addition of material layer or joining of material layersor parts of material layers to form a 3D structure, in a controlledmanner (e.g., under automated control). In the 3D printing process, thedeposited material can be fused, sintered, melted, bound or otherwiseconnected to form at least a part of the 3D object. Fusion, sintering,melting, binding or otherwise connecting the material is collectivelyreferred to herein as transforming the material (e.g., powder material).Fusing the material may include melting or sintering the material.Binding can comprise chemical bonding. Chemical bonding can comprisecovalent bonding. Examples of 3D printing include additive printing(e.g., layer by layer printing, or additive manufacturing). The 3Dprinting may further comprise subtractive printing.

The material may comprise elemental metal, metal alloy, ceramics, or anallotrope of elemental carbon. The allotrope of elemental carbon maycomprise amorphous carbon, graphite, graphene, diamond, or fullerene.The fullerene may be selected from the group consisting of a spherical,elliptical, linear, and tubular fullerene. The fullerene may comprise abuckyball or a carbon nanotube. In some embodiments, the material maycomprise an organic material, for example, a polymer or a resin. Thematerial may comprise a solid or a liquid. The solid material maycomprise powder material. The powder material may be coated by a coating(e.g., organic coating such as the organic material (e.g., plasticcoating)). The powder material may comprise sand. The liquid materialmay be compartmentalized into reactors, vesicles or droplets. Thecompartmentalized material may be compartmentalized in one or morelayers. The material may comprise at least two materials. The secondmaterial can be a reinforcing material (e.g., that forms a fiber). Thereinforcing material may comprise a carbon fiber, Kevlar®, Twaron®,ultra-high-molecular-weight polyethylene, or glass fiber. The materialcan comprise powder (e.g., granular material) or wires.

3D printing methodologies can comprise extrusion, wire, granular,laminated, light polymerization, or power bed and inkjet head 3Dprinting. Extrusion 3D printing can comprise robo-casting, fuseddeposition modeling (FDM) or fused filament fabrication (FFF). Wire 3Dprinting can comprise electron beam freeform fabrication (EBF3).Granular 3D printing can comprise direct metal laser sintering (DMLS),electron beam melting (EBM), selective laser melting (SLM), selectiveheat sintering (SHS), or selective laser sintering (SLS). Power bed andinkjet head 3D printing can comprise plaster-based 3D printing (PP).Laminated 3D printing can comprise laminated object manufacturing (LOM).Light polymerized 3D printing can comprise stereo-lithography (SLA),digital light processing (DLP) or laminated object manufacturing (LOM).

Three-dimensional printing methodologies may differ from methodstraditionally used in semiconductor device fabrication (e.g., vapordeposition, etching, annealing, masking, or molecular beam epitaxy). Insome instances, 3D printing may further comprise one or more printingmethodologies that are traditionally used in semiconductor devicefabrication. 3D printing methodologies can differ from vapor depositionmethods such as chemical vapor deposition, physical vapor deposition, orelectrochemical deposition. In some instances, 3D printing may furtherinclude vapor deposition methods.

The fundamental length scale of the printed 3D object (e.g., thediameter, spherical equivalent diameter, diameter of a bounding circle,or largest of height, width and length) can be at least about 50micrometers (μm), 80 μm, 100 μm, 120 μm, 150 μm, 170 μm, 200 μm, 230 μm,250 μm, 270 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 1millimeter (mm), 1.5 mm, 2 mm, 5 mm, 1 centimeter (cm), 1.5 cm, 2 cm, 10cm, 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 1 m, 2 m, 3m, 4 m, 5 m, 10 m, 50 m, 80 m, or 100 m. The fundamental length scale ofthe printed 3D object can be at most about 1000 m, 500 m, 100 m, 80 m,50 m, 10 m, 5 m, 4 m, 3 m, 2 m, 1 m, 90 cm, 80 cm, 60 cm, 50 cm, 40 cm,30 cm, 20 cm, 10 cm, or 5 cm. In some cases the fundamental length scaleof the printed 3D object may be in between any of the afore-mentionedfundamental length scales. For example, the fundamental length scale ofthe printed 3D object may be from about 50 μm to about 1000 m, fromabout 120 μm to about 1000 m, from about 120 μm to about 10 m, fromabout 200 μm to about 1 m, from about 150 μm to about 10 m.

The term “powder,” as used herein, generally refers to a solid havingfine particles. The powder may also be referred to as “particulatematerial.” Powders may be granular materials. In some examples, powdersare particles having an average fundamental length scale (e.g., thediameter, spherical equivalent diameter, diameter of a bounding circle,or largest of height, width and length) of at least about 5 nanometers(nm), 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm,500 nm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 35 μm, 30 μm, 40 μm, 45 μm, 50μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, or 100 μm. The particlescomprising the powder may have an average fundamental length scale of atmost about 100 μm, 80 μm, 75 μm, 70 μm, 65 μm, 60 μm, 55 μm, 50 μm, 45μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10 μm, 5 μm, 1 μm, 500 nm,400 nm, 300 nm, 200 nm, 100 nm, 50 nm, 40 nm, 30 nm, 20 nm, 10 nm, or 5nm. In some cases the powder may have an average fundamental lengthscale between any of the values of the average particle fundamentallength scale listed above. For example, the average fundamental lengthscale of the particles may be from about 5 nm to about 100 μm, fromabout 1 μm to about 100 μm, from about 15 μm to about 45 μm, from about5 μm to about 80 μm, from about 20 μm to about 80 μm, or from about 500nm to about 50 μm.

The powder can be composed of individual particles. The particles can bespherical, oval, prismatic, cubic, or irregularly shaped. The particlescan have a fundamental length scale. The powder can be composed of ahomogenously shaped particle mixture such that all of the particles havesubstantially the same shape and fundamental length scale magnitudewithin at most 1%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%,or 70% distribution of the fundamental length scale. In some cases thepowder can be a heterogeneous mixture such that the particles havevariable shape and/or fundamental length scale magnitude.

The term “base” as used herein, generally refers to any work piece onwhich a material used to form a 3D object, is placed on. The 3D objectmay be formed directly on the base, directly from the base, or adjacentto the base. The 3D object may be formed above the base. In someinstances, the 3D object does not contact the base. The 3D object may besuspended adjacent (e.g., above) the base. At times, the base may bedisposed on a substrate or on the bottom of an enclosure. The substratemay be disposed in an enclosure (e.g., a chamber). The enclosure canhave one or more walls formed of various types of materials, such aselemental metal, metal alloy (e.g., stainless steel), ceramics, or anallotrope of elemental carbon. The enclosure can have shapes of variouscross-sections, such as circular, triangular, square, rectangular,partial shapes, or combinations thereof. The enclosure may be thermallyinsulated. The enclosure may comprise thermal insulation. The enclosuremay comprise a sealing lip (e.g., flexible sealing lip). The sealing lipmay provide thermal insulation. The sealing lip may provideenvironmental (e.g., gasous) insulation. The enclosure may comprise anopen top. The enclosure may comprise an open side or an open bottom. Thebase can comprise an elemental metal, metal alloy, ceramic, allotrope ofcarbon, or polymer. The base can comprise stone, zeolite, clay or glass.The elemental metal can include iron, molybdenum, tungsten, copper,aluminum, gold, silver or titanium. A metal alloy may include steel(e.g., stainless steel). A ceramic material may include alumina. Thebase can include silicon, germanium, silica, sapphire, zinc oxide,carbon (e.g., graphite, Graphene, diamond, amorphous carbon, carbonfiber, carbon nanotube or fullerene), SiC, AlN, GaN, spinel, coatedsilicon, silicon on oxide, silicon carbide on oxide, gallium nitride,indium nitride, titanium dioxide, aluminum nitride. In some cases, thebase comprises a susceptor (i.e., a material that can absorbelectromagnetic energy and convert it to heat). The base, substrateand/or enclosure can be stationary or translatable.

In some examples the powder material, the base, or both the powder andthe base comprise a material wherein its constituents (e.g., atoms)readily lose their outer shell electrons, resulting in a free flowingcloud of electrons within their otherwise solid arrangement. In someexamples the powder, the base, or both the powder and the base comprisea material characterized in having high electrical conductivity, lowelectrical resistivity, high thermal conductivity, or high density. Thehigh electrical conductivity can be at least about 1*10⁵ Siemens permeter (S/m), 5*10⁵ S/m, 1*10⁶ S/m, 5*10⁶ S/m, 1*10⁷ S/m, 5*10⁷ S/m, or1*10⁸ S/m. The symbol “*” designates the mathematical operation “times.”The high electrical conductivity can be from about 1*10⁵ S/m to about1*10⁸ S/m. The low electrical resistivity may be at most about 1*10⁻⁵ohm times meter (Ω*m), 5*10⁻⁶ Ω*m, 1*10⁻⁶ Ω*m, 5*10⁻⁷ Ω*m, 1*10⁻⁷ Ω*m,5*10⁻⁸ or 1*10⁻⁸ Ω*m. The low electrical resistivity can be from about1×10⁻⁵ Ω*m to about 1×10⁻⁸ Ω*m. The high thermal conductivity may be atleast about 20 Watts per meters times degrees Kelvin (W/mK), 50 W/mK,100 W/mK, 150 W/mK, 200 W/mK, 205 W/mK, 300 W/mK, 350 W/mK, 400 W/mK,450 W/mK, 500 W/mK, 550 W/mK, 600 W/mK, 700 W/mK, 800 W/mK, 900 W/mK, or1000 W/mK. The high thermal conductivity can be from about 20 W/mK toabout 1000 W/mK. The high density may be at least about 1.5 grams percubic centimeter (g/cm³), 2 g/cm³, 3 g/cm³, 4 g/cm³, 5 g/cm³, 6 g/cm³, 7g/cm³, 8 g/cm³, 9 g/cm³, 10 g/cm³, 11 g/cm³, 12 g/cm³, 13 g/cm³, 14g/cm³, 15 g/cm³, 16 g/cm³, 17 g/cm³, 18 g/cm³, 19 g/cm³, 20 g/cm³, or 25g/cm³. The high density can be from about 1 g/cm³ to about 25 g/cm³.

Layers of a powder material can be provided additively or sequentially.At least parts of the layers can be transformed to form at least afraction (also used herein “a portion,” or “a part”) of a hardened(e.g., solidified) 3D object. At times a transformed powder layer maycomprise a cross section of a 3D object (e.g., a horizontal crosssection). A layer can have a thickness of at least about 0.1 micrometer(μm), 0.5 μm, 1.0 μm, 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, or 1000 μm. A layer can havea thickness of at most about 1000 μm, 900 μm, 800 μm, 700 μm, 60 μm, 500μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 75μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 5 μm, 1 μm, or 0.5 μm, or less. Alayer may have any value in between the aforementioned layer thicknessvalues. For example, the layer may be from about 1000 μm to about 0.1μm, 800 μm to about 1 μm, 600 μm to about 20 μm, 300 μm to about 30 μm,or 1000 μm to about 10 μm. The material composition of at least onelayer may differ from the material composition within at least one otherlayer in the powder bed. The materials of at least one layer may differin its crystal structure from the crystal structure of the materialwithin at least one other layer in the powder bed. The materials of atleast one layer may differ in its grain structure from the grainstructure of the material within at least one other layer in the powderbed. The materials of at least one layer may differ in the fundamentallength scale of its powder material from the fundamental length scale ofthe material within at least one other layer in the powder bed. A layermay comprise two or more material types at any combination. For example,two or more elemental metals, two or more metal alloys, two or moreceramics, two or more allotropes of elemental carbon. For example anelemental metal and a metal alloy, an elemental metal and a ceramic, anelemental metal and an allotrope of elemental carbon, a metal alloy anda ceramic, a metal alloy and an allotrope of elemental carbon, a ceramicand an allotrope of elemental carbon. All the layers deposited duringthe 3D printing process may be of the same material composition. In someinstances, a metal alloy is formed in situ during the process oftransforming the powder material. In some cases, the layers of differentcompositions can be deposited at a predetermined pattern. For example,each layer can have composition that increases or decreases in a certainelement, or in a certain material type. In some examples, each evenlayer may have one composition, and each odd layer may have anothercomposition. The varied compositions of the layer may follow amathematical series algorithm. In some cases, at least one area within alayer has a different material composition than another area within thatlayer.

A metallic material (e.g., elemental metal or metal alloy) can comprisesmall amounts of non-metallic materials, such as, for example, oxygen,sulfur, or nitrogen. In some cases, the metallic material can comprisethe non-metallic materials in trace amounts. A trace amount can be atmost about 100000 parts per million (ppm), 10000 ppm, 1000 ppm, 500 ppm,400 ppm, 200 ppm, 100 ppm, 50 ppm, 10 ppm, 5 ppm, or 1 ppm (on the basisof weight, w/w) of non-metallic material. A trace amount can comprise atleast about 10 ppt, 100 ppt, 1 ppb, 5 ppb, 10 ppb, 50 ppb, 100 ppb, 200ppb, 400 ppb, 500 ppb, 1000 ppb, 1 ppm, 10 ppm, 100 ppm, 500 ppm, 1000ppm, or 10000 ppm (on the basis of weight, w/w) of non-metallicmaterial. A trace amount can be any value between the afore-mentionedtrace amounts. For example, a trace amount can be from about 10 partsper trillion (ppt) to about 100000 ppm, from about 1 ppb to about 100000ppm, from about 1 ppm to about 10000 ppm, or from about 1 ppb to about1000 ppm.

In some instances, adjacent components are separated from one another byone or more intervening layers. In an example, a first layer is adjacentto a second layer when the first layer is in direct contact with thesecond layer. In another example, a first layer is adjacent to a secondlayer when the first layer is separated from the second layer by atleast one layer (e.g., a third layer). The intervening layer may be ofany layer size disclosed herein.

The term “auxiliary features,” as used herein, generally refers tofeatures that are part of a printed 3D object, but are not part of thedesired, intended, designed, ordered, or final 3D object. Auxiliaryfeatures (e.g., auxiliary supports) may provide structural supportduring and/or subsequent to the formation of the 3D object. Auxiliaryfeatures may enable the removal of energy from the 3D object that isbeing formed. Examples of auxiliary features comprise heat fins,anchors, handles, supports, pillars, columns, frame, footing, scaffold,flange, projection, protrusion, mold (a.k.a. mould) or otherstabilization features. In some instances, the auxiliary support is ascaffold that encloses the 3D object or part thereof. The scaffold maycomprise lightly sintered or lightly fused powder material.

The present disclosure provides systems, apparatuses and methods for 3Dprinting of an object from a material (e.g., powder material). Theobject can be pre-designed, or designed in real time (i.e., during theprocess of 3D printing). The 3D printing method can be an additivemethod in which a first layer is printed, and thereafter a volume of amaterial is added to the first layer as separate sequential layers. Eachadditional sequential layer can be added to the previous layer bytransforming (e.g., fusing, e.g., melting) a fraction of the powdermaterial.

Reference will now be made to the figures, wherein like numerals referto like parts throughout. It will be appreciated that the figures andfeatures therein are not necessarily drawn to scale.

An example of a system that can be used to generate an object by a 3Dprinting process is shown in FIG. 1. The system can comprise a powderbed 101 on a base 102. In some instances, the base 102 can be usedduring the formation process. In some situations, the nascent object, orobject formed during the 3D printing process, floats in the powder bed101 without touching the base 102. The base 102 can support at leastone, two, three, four, five, six, seven, eight, nine, ten, eleven,twelve, thirteen, fourteen, or fifteen powder layers. The base can beheated or cooled to a predetermined temperature or according to atemperature gradient. The temperature gradient can be defined for apredetermined amount of time. The predetermined temperature can be atleast about 10 degrees Celsius (° C.), 20° C., 25° C., 30° C., 40° C.,50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 150° C., 200° C., 250°C., 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C., 650°C., 700° C., 750° C., 800° C., 850° C., 900° C., or 1000° C. Thepredetermined temperature can be at most about 1000° C., 900° C., 800°C., 700° C., 600° C., 650° C., 600° C., 550° C., 500° C., 450° C., 400°C., 350° C., 300° C., 250° C., 200° C., 150° C., 100° C., 50° C., or 10°C. The predetermined temperature can be in between any of the values oftemperature listed above. For example, from about 10° C. to about 1000°C., from about 100° C. to about 600° C., from about 200° C. to about500° C., or from about 300° C. to about 450° C. The base can bethermostable. The base 102 can have walls. The base having walls can bereferred to as a container that accommodates a powder bed. The base(e.g., the walls of the base) may comprise temperature sensors (e.g.,one or more thermocouples). The temperature sensors may be operativelycoupled to a controller. The controller may comprise a processor (e.g.,a computer). In some instances, the temperature measures of the powderbed 101 and/or the base 102 can be made optically, for example by usingan infrared (IR) temperature sensor. The temperature sensors can monitorthe temperature at the edges of the powder bed, at one or more randomplaces in the powder bed, at the center of the powder bed, at the base,or in any combination thereof. The temperature sensors can monitor thetemperature at predetermined times, at random times, or at a whim. Insome cases the walls of the base can be insulated. The base (e.g., thewalls of the base) can be heated or cooled continuously or sporadicallyto maintain a desired temperature of the powder bed. The powder bed canhave an exposed top surface, a covered top surface, or a partiallyexposed and partially covered top surface. The powder bed can be atleast about 1 mm, 10 mm, 25 mm, 50 mm, 100 mm, 200 mm, 300 mm, 400 mm,or 500 mm wide. The powder bed can be at least about 1 mm, 10 mm, 25 mm,50 mm, 100 mm, 200 mm, 300 mm, 400 mm, or 500 mm deep. The powder bedcan be at least about 1 mm, 10 mm, 25 mm, 50 mm, 100 mm, 200 mm, 300 mm,400 mm, or 500 mm long. The powder bed 101 on the base 102 can beadjacent to a powder reservoir (e.g., 103). The powder reservoir can bedisposed in a container (e.g., 104). The container may be a stationaryor a translatable. The powder bed 101 can be maintained at or nearthermal equilibrium throughout the printing process. The averagetemperature of the powder bed can thermally fluctuate by at least 0.1°C., 0.2° C., 0.3° C., 0.4° C., 0.5° C., 0.6° C., 0.7° C., 0.8° C., 0.9°C., 1° C., 2° C., 3, ° C. 4° C., 5° C., 6° C., 7° C., 8° C., 9° C., 10°C., 15° C., 20° C., 30° C., 40° C., or 50° C., or less during theprinting process. The average temperature of the powder bed canthermally fluctuate by at most about 50° C., 40° C., 30° C., 20° C., 10°C., or 5° C. during the printing process. The average temperature of thepowder bed can thermally fluctuate between any of the aforementionedtemperature fluctuation values. For example, the average temperature ofthe powder bed can fluctuate by a temperature range of from 50° C. to 5°C., or from 30° C. to 5° C.

During the printing process powder from the powder reservoir (e.g., 103)can be moved from the reservoir to the base (e.g., 102) to provide newpowder, recycled powder, cool powder or any combination thereof to thepowder bed (e.g., 101) on the base. Powder can be moved from the powderreservoir to the powder bed by a layer dispensing mechanism (also herein“translating mechanism” e.g., 105. Also herein “layer addingmechanism”). The layer dispensing mechanism can be a translatingmechanism (e.g., translating device), which can include one or moremoving parts. The layer dispensing mechanism can be a devise capable ofmoving the powder, depositing the powder, leveling the powder, removingthe powder, or any combination thereof.

The layer dispensing mechanism may be translated substantiallyhorizontally, vertically or at an angle. The layer dispensing mechanismmay be translated laterally. In some examples, the base, the substrate,the enclosure, or the powder bed may be translatable. The layerdispensing mechanism may comprise springs. The base, substrate,enclosure or the powder bed may be translated substantially horizontally(e.g., right to left and vice versa), substantially vertically (e.g.,top to bottom and vice versa) or at an angle. At least one of theenclosure, the substrate, and the base may comprise a lowerable platform(e.g., an elevator). The elevator may translate the powder bed (or thecontainer thereof) to a first position. Powder may be deposited in thepowder bed (or in the container thereof) in the first position. Thepowder bed may be subsequently translated to a second position. In someexamples, the second position is lower than the first position. In thesecond position the powder bed may be vertically farther from the layerdispensing mechanism, as compared to the first position. In someexamples, the powder bed or the container thereof may be stationary. Insome examples, the second position is higher than the first position(e.g., by the elevator). In some examples, layer dispensing mechanismmay be able to move to the second position. The side of the layerdispensing mechanism that is closest to the exposed surface of thepowder bed is designated herein as the bottom of the layer dispensingmechanism. When the powder bed (or the container thereof) is in thesecond position, at least part of the deposited powder may be locatedvertically above the bottom of the layer dispensing mechanism. At times,the container accommodating the powder bed may be devoid of powdermaterial. At times, the container accommodating the powder bed comprisespowder material. The layer dispensing mechanism may be translatedlaterally along the powder bed such that at least part of the powdermaterial obstructs the movement of the layer dispensing mechanism in thesecond position. The layer dispensing mechanism may push, compress orcollect the obstructing powder material as it moves laterally. The layerdispensing mechanism may level the powder material on its lateralmovement along the powder bed (e.g., along the width or the length ofthe powder bed). The leveling of the powder may result in generating aplane with substantially planar uniformity in at least one plane (e.g.,a horizontal plane) at the top (i.e., exposed surface) of the powderbed. The leveling of the powder may result in generating a plane withaverage planar uniformity in at least one plane (e.g., horizontal plane)at the top of the layer of powder material. The average plane may be aplane defined by a least squares planar fit of the top-most part of thesurface of the layer of powder material. The average plane may be aplane calculated by averaging the powder height at each point on the topsurface of the powder bed. The layer dispensing mechanism (e.g., 105)can comprise a roller, a brush, a rake (e.g., saw-tooth rake ordowel-tooth rake), a plough, a spatula or a knife blade. The layerdispensing mechanism may comprise a vertical cross section (e.g., sidecross section) of a circle, triangle, square, pentagon, hexagon,octagon, or any other polygon. In some cases, the layer dispensingmechanism can comprise a roller. The roller can be a smooth roller. Theroller can be a rough roller. The roller may have protrusions ordepressions. The extrusions may be bendable extrusions (e.g., brush);the extrusion may be hard extrusions (e.g., rake). The extrusions maycomprise a pointy end, a round end or a blunt end. The protrusions ordepressions may form a pattern on the roller, or be randomly situated onthe roller. Alternatively or additionally, the layer dispensingmechanism can comprise a plough or a rake. The layer dispensingmechanism may comprise a blade. The blade may comprise a planar concave,planar convex, chisel shaped, or wedge shaped blade. The blade may havea chisel or wedge shape, as well as a concave top surface (FIG. 12C at1212) that may allow powder to accumulate on its top (e.g., 1214). Theblade may have a chisel or wedge shape (e.g., FIG. 12B at 1207) andallow the powder to slide on its top. (e.g., 1209). The blade maycomprise a sharp edge or a curved surface. The curved surface maycomprise a radius of curvature of at least about 0.5 mm, 1 mm, 2 mm, 3mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or 11 mm. The radius ofcurvature may be of at most about 12 mm, 11 mm, 10 mm, 9 mm, 8 mm, 7 mm,6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm. The radius of curvature of thecurved surface may be of any value between the aforementioned values(e.g., from about 0.5 mm to about 12 mm, from about 0.5 mm to about 5mm, or from about 5 mm to about 12 mm). The layer dispensing mechanismmay be comprised of a ceramic, metallic, metal alloy (e.g., steel) orpolymeric material (e.g., rubber). For example, the layer dispensingmechanism (e.g., 105) can comprise a rake with vertical features thatcan be used to move the powder, and vertical opening in between thefeatures. In some cases the layer dispensing mechanism can have asubstantially convex, concave, slanted, or straight edge that contactthe powder bed. The edge of the layer dispensing mechanism can beperpendicular, parallel or at an acute angle that is between zero and 90degrees with respect to the surface of the powder bed. The layerdispensing mechanism can be configured to provide a smooth, even, and/orleveled layer of recycled powder, new powder, cool powder, hot powder,powder at ambient temperatures, or any combination thereof across thetop surface of the powder bed. The powder material can be chosen suchthat the powder material is the desired or otherwise predeterminedmaterial for the object. In some cases, a layer of the 3D objectcomprises a single type of material. In some examples, a layer of the 3Dobject may comprise a single elemental metal type, or a single alloytype. In some examples, a layer within the 3D object may compriseseveral types of material (e.g., an elemental metal and an alloy, analloy and a ceramics, an alloy and an allotrope of elemental carbon). Incertain embodiments each type of material comprises only a single memberof that type. For example: a single member of elemental metal (e.g.,iron), a single member of metal alloy (e.g., stainless steel), a singlemember of ceramic material (e.g., silicon carbide or tungsten carbide),or a single member (e.g., an allotrope) of elemental carbon (e.g.,graphite). In some cases, a layer of the 3D object comprises more thanone type of material. In some cases, a layer of the 3D object comprisesmore than one member of a material type.

The elemental metal can be an alkali metal, an alkaline earth metal, atransition metal, a rare earth element metal, or another metal. Thealkali metal can be Lithium, Sodium, Potassium, Rubidium, Cesium, orFrancium. The alkali earth metal can be Beryllium, Magnesium, Calcium,Strontium, Barium, or Radium. The transition metal can be Scandium,Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper,Zinc, Yttrium, Zirconium, Platinum, Gold, Rutherfordium, Dubnium,Seaborgium, Bohrium, Hassium, Meitnerium, Ununbium, Niobium, Iridium,Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver, Cadmium,Hafnium, Tantalum, Tungsten, Rhenium, or Osmium. The transition metalcan be mercury. The rare earth metal can be a lantanide, or an actinide.The lantinide metal can be Lanthanum, Cerium, Praseodymium, Neodymium,Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium,Holmium, Erbium, Thulium, Ytterbium, or Lutetium. The actinide metal canbe Actinium, Thorium, Protactinium, Uranium, Neptunium, Plutonium,Americium, Curium, Berkelium, Californium, Einsteinium, Fermium,Mendelevium, Nobelium, or Lawrencium. The other metal can be Aluminium,Gallium, Indium, Tin, Thallium, Lead, or Bismuth.

The metal alloy can be an iron based alloy, nickel based alloy, cobaltbased allow, chrome based alloy, cobalt chrome based alloy, titaniumbased alloy, magnesium based alloy, copper based alloy, or anycombination thereof. The alloy may comprise an oxidation or corrosionresistant alloy. The alloy may comprise a super alloy (e.g., Inconel).The super alloy may comprise Inconel 600, 617, 625, 690, 718, or X-750.The metal (e.g., alloy or elemental) may comprise an alloy used forapplications in industries comprising aerospace, automotive, marine,locomotive, satellite, defense, oil & gas, energy generation,semiconductor, fashion, construction, agriculture, printing, or medical.The metal (e.g., alloy or elemental) may comprise an alloy used forproducts comprising, devices, medical devices (human & veterinary),machinery, cell phones, semiconductor equipment, generators, engines,pistons, electronics (e.g., circuits), electronic equipment, agricultureequipment, motor, gear, transmission, communication equipment, computingequipment (e.g., laptop, cell phone, i-pad), air conditioning,generators, furniture, musical equipment, art, jewelry, cookingequipment, or sport gear. The metal (e.g., alloy or elemental) maycomprise an alloy used for products for human or veterinary applicationscomprising implants, or prosthetics. The metal alloy may comprise analloy used for applications in the fields comprising human or veterinarysurgery, implants (e.g., dental), or prosthetics.

The methods, apparatuses and systems of the present disclosure can beused to form 3D objects for various uses and applications. Such uses andapplications include, without limitation, electronics, components ofelectronics (e.g., casings), machines, parts of machines, tools,implants, prosthetics, fashion items, clothing, shoes or jewelry. Theimplants may be directed (e.g., integrated) to a hard, a soft tissue orto a combination of hard and soft tissues. The implants may formadhesion with hard or soft tissue. The machines may include motor ormotor parts. The machines may include a vehicle. The machines maycomprise aerospace related machines. The machines may comprise airbornemachines. The vehicle may include airplane, drone, car, train, bicycle,boat, or shuttle (e.g., space shuttle). The machine may include asatellite or a missile. The uses and application may include 3D objectsrelating to the industries and/or products listed above.

In some instances, the iron alloy comprises Elinvar, Fernico,Ferroalloys, Invar, Iron hydride, Kovar, Spiegeleisen, Staballoy(stainless steel), or Steel. In some instances the metal alloy is steel.The Ferroalloy may comprise Ferroboron, Ferrocerium, Ferrochrome,Ferromagnesium, Ferromanganese, Ferromolybdenum, Ferronickel,Ferrophosphorus, Ferrosilicon, Ferrotitanium, Ferrouranium, orFerrovanadium. The iron alloy may include cast iron, or pig iron. Thesteel may include Bulat steel, Chromoly, Crucible steel, Damascus steel,Hadfield steel, High speed steel, HSLA steel, Maraging steel, Reynolds531, Silicon steel, Spring steel, Stainless steel, Tool steel,Weathering steel, or Wootz steel. The high-speed steel may includeMushet steel. The stainless steel may include AL-6XN, Alloy 20,celestrium, marine grade stainless, Martensitic stainless steel,surgical stainless steel, or Zeron 100. The tool steel may includeSilver steel. The steel may comprise stainless steel, Nickel steel,Nickel-chromium steel, Molybdenum steel, Chromium steel,Chromium-vanadium steel, Tungsten steel, Nickel-chromium-molybdenumsteel, or Silicon-manganese steel. The steel may be comprised of anySociety of Automotive Engineers (SAE) grade such as 440F, 410, 312, 430,440A, 440B, 440C, 304, 305, 304L, 304L, 301, 304LN, 301LN, 2304, 316,316L, 316LN, 316, 316LN, 316L, 316L, 316, 317L, 2205, 409, 904L, 321,254SMO, 316Ti, 321H, or 304H. The steel may comprise stainless steel ofat least one crystalline structure selected from the group consisting ofaustenitic, superaustenitic, ferritic, martensitic, duplex, andprecipitation-hardening martensitic. Duplex stainless steel may be leanduplex, standard duplex, super duplex, or hyper duplex. The stainlesssteel may comprise surgical grade stainless steel (e.g., austenitic 316,martensitic 420, or martensitic 440). The austenitic 316 stainless steelmay include 316L, or 316LVM. The steel may include 17-4 PrecipitationHardening steel (also known as type 630, a chromium-copper precipitationhardening stainless steel, 17-4 PH steel).

The titanium-based alloys may include alpha alloys, near alpha alloys,alpha and beta alloys, or beta alloys. The titanium alloy may comprisegrade 1, 2, 2H, 3, 4, 5, 6, 7, 7H, 8, 9, 10, 11, 12, 13, 14, 15, 16,16H, 17, 18, 19, 20, 21, 2, 23, 24, 25, 26, 26H, 27, 28, 29, 30, 31, 32,33, 34, 35, 36, 37, 38, or higher. In some instances the titanium basealloy includes Ti-6Al-4V or Ti-6Al-7Nb.

The Nickel alloy may include Alnico, Alumel, Chromel, Cupronickel,Ferronickel, German silver, Hastelloy, Inconel, Monel metal, Nichrome,Nickel-carbon, Nicrosil, Nisil, Nitinol, or Magnetically “soft” alloys.The magnetically “soft” alloys may comprise Mu-metal, Permalloy,Supermalloy, or Brass. The brass may include Nickel hydride, Stainlessor Coin silver. The cobalt alloy may include Megallium, Stellite (e.g.Talonite), Ultimet, or Vitallium. The chromium alloy may includechromium hydroxide, or Nichrome.

The aluminum alloy may include AA-8000, Al—Li (aluminum-lithium),Alnico, Duralumin, Hiduminium, Kryron Magnalium, Nambe,Scandium-aluminum, or Y alloy. The magnesium alloy may be Elektron,Magnox, or T-Mg—Al—Zn (Bergman phase) alloy.

The copper alloy may comprise Arsenical copper, Beryllium copper,Billon, Brass, Bronze, Constantan, Copper hydride, Copper-tungsten,Corinthian bronze, Cunife, Cupronickel, Cymbal alloys, Devarda's alloy,Electrum, Hepatizon, Heusler alloy, Manganin, Molybdochalkos, Nickelsilver, Nordic gold, Shakudo, or Tumbaga. The Brass may include Calaminebrass, Chinese silver, Dutch metal, Gilding metal, Muntz metal,Pinchbeck, Prince's metal, or Tombac. The Bronze may include Aluminumbronze, Arsenical bronze, Bell metal, Florentine bronze, Guanin,Gunmetal, Glucydur, Phosphor bronze, Ormolu, or Speculum metal.

The powder can be configured to provide support to the 3D object as itis formed in the powder bed by the 3D printing process. In someinstances, a low flowability powder can be capable of supporting a 3Dobject better than a high flowability powder. A low flowability powdercan be achieved inter alia with a powder composed of relatively smallparticles, with particles of non-uniform size or with particles thatattract each other. The powder may be of low, medium or highflowability. The powder material may have compressibility of at leastabout 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% in response to anapplied force of 15 kilo Pascals (kPa). The powder may have acompressibility of at most about 9%, 8%, 7%, 6%, 5%, 4.5%, 4.0%, 3.5%,3.0%, 2.5%, 2.0%, 1.5%, 1.0%, or 0.5% in response to an applied force of15 kilo Pascals (kPa). The powder may have a basic flow energy of atleast about 100 milli-Joule (mJ), 200 mJ, 300 mJ, 400 mJ, 450 mJ, 500mJ, 550 mJ, 600 mJ, 650 mJ, 700 mJ, 750 mJ, 800 mJ, or 900 mJ. Thepowder may have a basic flow energy of at most about 200 mJ, 300 mJ, 400mJ, 450 mJ, 500 mJ, 550 mJ, 600 mJ, 650 mJ, 700 mJ, 750 mJ, 800 mJ, 900mJ, or 1000 mJ. The powder may have basic flow energy in between theabove listed values of basic flow energy. For example, the powder mayhave a basic flow energy from about 100 mJ to about 1000 mJ, from about100 mJ to about 600 mJ, or from about 500 mJ to about 1000 mJ. Thepowder may have a specific energy of at least about 1.0 milli-Joule pergram (mJ/g), 1.5 mJ/g, 2.0 mJ/g, 2.5 mJ/g, 3.0 mJ/g, 3.5 mJ/g, 4.0 mJ/g,4.5 mJ/g, or 5.0 mJ/g. The powder may have a specific energy of at most5.0 mJ/g, 4.5 mJ/g, 4.0 mJ/g, 3.5 mJ/g, 3.0 mJ/g, 2.5 mJ/g, 2.0 mJ/g,1.5 mJ/g, or 1.0 mJ/g. The powder may have a specific energy in betweenany of the above values of specific energy. For example, the powder mayhave a specific energy from about 1.0 mJ/g to about 5.0 mJ/g, from about3.0 mJ/g to about 5 mJ/g, or from about 1.0 mJ/g to about 3.5 mJ/g.

The 3D object can have auxiliary features that can be supported by thepowder bed. The 3D object can have auxiliary features that can besupported by the powder bed and not touch the base, substrate, containeraccommodating the powder bed, or the bottom of the enclosure. Thethree-dimensional part (3D object) in a complete or partially formedstate can be completely supported by the powder bed (e.g., withouttouching the substrate, base, container accommodating the powder bed, orenclosure). The three-dimensional part (3D object) in a complete orpartially formed state can be completely supported by the powder bed(e.g., without touching anything except the powder bed). The 3D objectin a complete or partially formed state can be suspended in the powderbed without resting on any additional support structures. In some cases,the 3D object in a complete or partially formed (i.e., nascent) statecan float in the powder bed.

The 3D object can have various surface roughness profiles, which may besuitable for various applications. The surface roughness may be thedeviations in the direction of the normal vector of a real surface, fromits ideal form. The surface roughness may be measured as the arithmeticaverage of the roughness profile (hereinafter “Ra”). Ra may use absolutevalues. The 3D object can have a Ra value of at least about 200 μm, 100μm, 75 μm, 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10μm, 7 μm, 5 μm, 3 μm, 1 μm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 50nm, 40 nm, or 30 nm. The formed object can have a Ra value of at mostabout 200 μm, 100 μm, 75 μm, 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm,20 μm, 15 μm, 10 μm, 7 μm, 5 μm, 3 μm, 1 μm, 500 nm, 400 nm, 300 nm, 200nm, 100 nm, 50 nm, 40 nm, or 30 nm. The 3D object can have a Ra valuebetween any of the aforementioned Ra values. For example, the Ra valuecan be from about 30 nm to about 50 μm, from about 5 μm to about 40 μm,from about 3 μm to about 30 μm, from about 10 nm to about 50 μm, or fromabout 15 nm to about 80 μm. The Ra values may be measured by electronmicroscopy (e.g., scanning electron microscopy), scanning tunnelingmicroscopy, atomic force microscopy, optical microscopy (e.g., confocal,laser), or ultrasound. The Ra values may be measured by a contact or bya non-contact method.

The 3D object may be composed of successive layers (e.g., successivecross sections) of solid material that originated from a transformedmaterial (e.g., fused, sintered, melted, bound or otherwise connectedpowder material). The transformed powder material may be connected to ahardened (e.g., solidified) material. The hardened material may residewithin the same layer, or in another layer (e.g., a previous layer). Insome examples, the hardened material comprises disconnected parts of thethree dimensional object, that are subsequently connected by the newlytransformed material (e.g., by fusing, sintering, melting, binding orotherwise connecting a powder material).

A cross section (e.g., vertical cross section) of the generated (i.e.,formed) 3D object may reveal a microstructure or a grain structureindicative of a layered deposition. Without wishing to be bound totheory, the microstructure or grain structure may arise due to thesolidification of transformed powder material that is typical to and/orindicative of the 3D printing method. For example, a cross section mayreveal a microstructure resembling ripples or waves that are indicativeof solidified melt pools that may be formed during the 3D printingprocess. The repetitive layered structure of the solidified melt poolsmay reveal the orientation at which the part was printed. The crosssection may reveal a substantially repetitive microstructure or grainstructure. The microstructure or grain structure may comprisesubstantially repetitive variations in material composition, grainorientation, material density, degree of compound segregation or ofelement segregation to grain boundaries, material phase, metallurgicalphase, crystal phase, crystal structure, material porosity, or anycombination thereof. The microstructure or grain structure may comprisesubstantially repetitive solidification of layered melt pools. Thesubstantially repetitive microstructure may have an average layer sizeof at least about 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm,60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350μm, 400 μm, 450 μm, or 500 μm. The substantially repetitivemicrostructure may have an average layer size of at most about 500 μm,450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 90 μm,80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, or 10 μm. Thesubstantially repetitive microstructure may have an average layer sizeof any value between the aforementioned values of layer size. Forexample, the substantially repetitive microstructure may have an averagelayer size from about 0.5 μm to about 500 μm, from about 15 μm to about50 μm, from about 5 μm to about 150 μm, from about 20 μm to about 100μm, or from about 10 μm to about 80 μm.

The printed 3D object may be printed without the use of auxiliaryfeatures, may printed using a reduced amount of auxiliary features, orprinted using spaced apart auxiliary features. In some embodiments, theprinted 3D object may be devoid of one or more auxiliary supportfeatures or auxiliary support feature marks that are indicative of apresence or removal of the auxiliary support features. The 3D object maybe devoid of one or more auxiliary support features and of one or moremarks of an auxiliary feature (including a base structure) that wasremoved (e.g., subsequent to the generation of the 3D object). Theprinted 3D object may comprise a single auxiliary support mark. Thesingle auxiliary feature (e.g., auxiliary support or auxiliarystructure) may be a base, a substrate, or a mold. The auxiliary supportmay be adhered to the base, substrate, or mold. The 3D object maycomprise marks belonging to one or more auxiliary structures. The 3Dobject may comprise two or more marks belonging to auxiliary features.The 3D object may be devoid of marks pertaining to an auxiliary support.The 3D object may be devoid of an auxiliary support. The 3D object maybe devoid of one or more auxiliary support features and of one or moremarks pertaining to a auxiliary support. The mark may comprise variationin grain orientation, variation in layering orientation, variation inlayering thickness, variation in material density, variation in thedegree of compound segregation to grain boundaries, variation inmaterial porosity, variation in the degree of element segregation tograin boundaries, variation in material phase, variation inmetallurgical phase, variation in crystal phase, or variation in crystalstructure, where the variation may not have been created by the geometryof the 3D object alone, and may thus be indicative of a prior existingauxiliary support that was removed. The variation may be forced upon thegenerated 3D object by the geometry of the support. In some instances,the 3D structure of the printed object may be forced by the auxiliarysupport (e.g., by a mold). For example, a mark may be a point ofdiscontinuity that is not explained by the geometry of the 3D object,which does not include any auxiliary supports. A mark may be a surfacefeature that cannot be explained by the geometry of a 3D object, whichdoes not include any auxiliary supports (e.g., a mold). The two or moreauxiliary features or auxiliary support feature marks may be spacedapart by a spacing distance of at least 1.5 millimeters (mm), 2 mm, 2.5mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm,12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, 15 mm, 15.5 mm, 16 mm, 20 mm,20.5 mm, 21 mm, 25 mm, 30 mm, 30.5 mm, 31 mm, 35 mm, 40 mm, 40.5 mm, 41mm, 45 mm, 50 mm, 80 mm, 100 mm, 200 mm 300 mm, or 500 mm. The two ormore auxiliary support features or auxiliary support feature marks maybe spaced apart by a spacing distance of at most 1.5 mm, 2 mm, 2.5 mm, 3mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, 15 mm, 15.5 mm, 16 mm, 20 mm, 20.5mm, 21 mm, 25 mm, 30 mm, 30.5 mm, 31 mm, 35 mm, 40 mm, 40.5 mm, 41 mm,45 mm, 50 mm, 80 mm, 100 mm, 200 mm 300 mm, or 500 mm. The two or moreauxiliary support features or auxiliary support feature marks may bespaced apart by a spacing distance of any value between theaforementioned auxiliary support space values. For example, theauxiliary features can be spaced apart by a distance from 1.5 mm to 500mm, from 2 mm to 100 mm, from 15 mm to 50 mm, or from 45 mm to 200 mm(collectively referred to herein as the “auxiliary feature spacingdistance”).

The 3D object may comprise a layered structure indicative of 3D printingprocess that is devoid of one or more auxiliary support features or oneor more auxiliary support feature marks that are indicative of apresence or removal of the one or more auxiliary support features. The3D object may comprise a layered structure indicative of 3D printingprocess, which includes one, two or more auxiliary support marks. Thesupports or support marks can be on the surface of the 3D object. Theauxiliary supports or support marks can be on an external, on aninternal surface (e.g., a cavity within the 3D object), or both. Thelayered structure can have a layering plane. In one example, twoauxiliary support features or auxiliary support feature or auxiliarysupport feature mark present in the 3D object may be spaced apart by theauxiliary feature spacing distance. The acute (i.e., sharp) angle alphabetween the straight line connecting the two auxiliary supports orauxiliary support marks and the direction of normal to the layeringplane may be at least about 45 degrees (°), 50°, 55°, 60°, 65°, 70°,75°, 80°, or 85°. The acute angle alpha between the straight lineconnecting the two auxiliary supports or auxiliary support marks and thedirection of normal to the layering plane may be at most about 90°, 85°,80°, 75°, 70°, 65°, 60°, 55°, 50°, or 45°. The acute angle alpha betweenthe straight line connecting the two auxiliary supports or auxiliarysupport marks and the direction of normal to the layering plane may beany angle range between the aforementioned angles. For example, fromabout 45 degrees (°), to about 90°, from about 60° to about 90°, fromabout 75° to about 90°, from about 80° to about 90°, from about 85° toabout 90°. The acute angle alpha between the straight line connectingthe two auxiliary supports or auxiliary support marks and the directionof normal to the layering plane may from about 87° to about 90°. The twoauxiliary supports or auxiliary support marks can be on the samesurface. The same surface can be an external surface or on an internalsurface (e.g., a surface of a cavity within the 3D object). When theangle between the shortest straight line connecting the two auxiliarysupports or auxiliary support marks and the direction of normal to thelayering plane is greater than 90 degrees, one can consider thecomplementary acute angle. In some embodiments, any two auxiliarysupports or auxiliary support marks are spaced apart by at least about10.5 millimeters or more. In some embodiments, any two auxiliarysupports or auxiliary support marks are spaced apart by at least about40.5 millimeters or more. In some embodiments, any two auxiliarysupports or auxiliary support marks are spaced apart by the auxiliaryfeature spacing distance.

The one or more layers within the 3D object may be substantially flat.The substantially flat one or more layers may have a large radius ofcurvature. The one or more layers may have a radius of curvature equalto the surface radius of curvature. The surface radius of curvature mayhave a value of at least about 0.1 centimeter (cm), 0.2 cm, 0.3 cm, 0.4cm, 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1 cm, 5 cm, 10 cm, 20 cm, 30cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 1 meter (m), 1.5 m, 2 m,2.5 m, 3 m, 3.5 m, 4 m, 4.5 m, 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 50 m,or 100 m. The surface radius of curvature may have a value of at mostabout 0.1 centimeter (cm), 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, 0.6 cm, 0.7cm, 0.8 cm, 0.9 cm, 1 cm, 5 cm, 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 60cm, 70 cm, 80 cm, 90 cm, 1 meter (m), 1.5 m, 2 m, 2.5 m, 3 m, 3.5 m, 4m, 4.5 m, 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 50 m, or 100 m. The surfaceradius of curvature may have any value between any of theafore-mentioned values of the radius of curvature. For example, fromabout 10 cm to about 90 m, from about 50 cm to about 10 m, from about 5cm to about 1 m, from about 50 cm to about 5 m, or from about 40 cm toabout 50 m. In some examples, the one or more layers may be included ina planar section of the 3D object, or may be a planar 3D object. Theradius of curvature may be measured by optical microscopy, electronmicroscopy, confocal microscopy, atomic force microscopy, spherometer,caliber (e.g., vernier caliber), positive lens, interferometer, or laser(e.g., tracker).

Each layer of the three dimensional structure can be made of a singlematerial or of multiple materials as disclosed herein. A layer of the 3Dobject may be composed of a composite material. The 3D object may becomposed of a composite material.

The 3D object may comprise a point X, which resides on the surface ofthe 3D object and Y, which is the closest auxiliary support or auxiliarysupport mark to X. In some embodiments, X is spaced apart from Y by theauxiliary feature spacing distance. The acute angle between the shorteststraight line XY and the direction of normal to the layering plane mayhave the value of the acute angle alpha. When the angle between theshortest straight line XY and the direction normal to the layering planeis greater than 90 degrees, one can consider the complementary acuteangle. In some embodiments, X is spaced apart from Y by at least about10.5 millimeters or more. In some embodiments, X is spaced apart from Yby at least about 40.5 millimeters or more.

The 3D object may comprise a layering plane N of the layered structure.The 3D object may comprise points X and Y, which reside on the surfaceof the 3D object, wherein X is spaced apart from Y by at least about10.5 millimeters or more. In some embodiments, X is spaced apart from Yby the auxiliary feature spacing distance. A sphere of radius XY that iscentered at X lacks one or more auxiliary supports or one or moreauxiliary support marks that are indicative of a presence or removal ofthe one or more auxiliary support features. In some embodiments, Y isspaced apart from X by at least about 10.5 millimeters or more. An acuteangle between the straight line XY and the direction of normal to N maybe from about 45 degrees to about 90 degrees. The acute angle betweenthe straight line XY and the direction of normal to the layering planemay be of the value of the acute angle alpha. When the angle between thestraight line XY and the direction of normal to N is greater than 90degrees, one can consider the complementary acute angle. The layerstructure may comprise any material used for 3D printing describedherein. Each layer of the three dimensional structure can be made of asingle material or of multiple materials. Sometimes one part of thelayer may comprise one material, and another part may comprise a secondmaterial different than the first material.

The straight line XY, or the surface having a fundamental length scale(e.g., radius) of XY may be substantially flat. For example, thesubstantially flat surface may have a large radius of curvature. Thestraight line XY or the surface having a radius (or a fundamental lengthscale of) XY may have a radius of curvature equal to the values of thesurface radius of curvature. The radius of curvature of the straightline XY may be normal to the length of the line XY. The curvature of thestraight line XY may be the curvature along the length of the line XY.

One or more sensors (at least one sensor) can monitor the amount ofpowder in the powder bed. The at least one sensor can be operativelycoupled to a control system (e.g., computer control system). The sensormay comprise light sensor, acoustic sensor, vibration sensor, chemicalsensor, electrical sensor, magnetic sensor, fluidity sensor, movementsensor, speed sensor, position sensor, pressure sensor, force sensor,density sensor, or proximity sensor. The sensor may include temperaturesensor, weight sensor, powder level sensor, gas sensor, or humiditysensor. The gas sensor may sense any of the gas delineated herein. Thetemperature sensor may comprise Bolometer, Bimetallic strip,calorimeter, Exhaust gas temperature gauge, Flame detection, Gardongauge, Golay cell, Heat flux sensor, Infrared thermometer,Microbolometer, Microwave radiometer, Net radiometer, Quartzthermometer, Resistance temperature detector, Resistance thermometer,Silicon band gap temperature sensor, Special sensor microwave/imager,Temperature gauge, Thermistor, Thermocouple, Thermometer, or Pyrometer.The pressure sensor may comprise Barograph, Barometer, Boost gauge,Bourdon gauge, Hot filament ionization gauge, Ionization gauge, McLeodgauge, Oscillating U-tube, Permanent Downhole Gauge, Piezometer, Piranigauge, Pressure sensor, Pressure gauge, Tactile sensor, or Time pressuregauge. The position sensor may comprise Auxanometer, Capacitivedisplacement sensor, Capacitive sensing, Free fall sensor, Gravimeter,Gyroscopic sensor, Impact sensor, Inclinometer, Integrated circuitpiezoelectric sensor, Laser rangefinder, Laser surface velocimeter,LIDAR, Linear encoder, Linear variable differential transformer (LVDT),Liquid capacitive inclinometers, Odometer, Photoelectric sensor,Piezoelectric accelerometer, Rate sensor, Rotary encoder, Rotaryvariable differential transformer, Selsyn, Shock detector, Shock datalogger, Tilt sensor, Tachometer, Ultrasonic thickness gauge, Variablereluctance sensor, or Velocity receiver. The optical sensor may comprisea Charge-coupled device, Colorimeter, Contact image sensor,Electro-optical sensor, Infra-red sensor, Kinetic inductance detector,light emitting diode (e.g., light sensor), Light-addressablepotentiometric sensor, Nichols radiometer, Fiber optic sensors, Opticalposition sensor, Photo detector, Photodiode, Photomultiplier tubes,Phototransistor, Photoelectric sensor, Photoionization detector,Photomultiplier, Photo resistor, Photo switch, Phototube,Scintillometer, Shack-Hartmann, Single-photon avalanche diode,Superconducting nanowire single-photon detector, Transition edge sensor,Visible light photon counter, or Wave front sensor. The weight of thepowder bed can be monitored by one or more weight sensors in, oradjacent to, the powder. For example, a weight sensor in the powder bedcan be at the bottom of the powder bed. The weight sensor can be betweenthe bottom of the enclosure and the substrate. The weight sensor can bebetween the bottom of the enclosure and the base. The weight sensor canbe between the bottom of the enclosure and the powder bed. A weightsensor can comprise a pressure sensor. The weight sensor may comprise aspring scale, a hydraulic scale, a pneumatic scale, or a balance. Atleast a portion of the pressure sensor can be exposed on a bottomsurface of the powder bed. In some cases, the weight sensor can comprisea button load cell. The button load cell can sense pressure from powderadjacent to the load cell. In another example, one or more sensors(e.g., optical sensors or optical level sensors) can be providedadjacent to the powder bed such as above, below, or to the side of thepowder bed. In some examples, the one or more sensors can sense thepowder level. In some cases, the powder level sensors can monitor powderlevel ahead of a leveling mechanism (e.g., leveling device). The powderlevel sensor can be in communication with a powder dispensing system(also referred to herein as powder dispensing member, or powderdispensing mechanism configured to dispense powder when the powder levelsensor detects a powder level below a predetermined threshold.Alternatively, or additionally a sensor can be configured to monitor theweight of the powder bed by monitoring a weight of a structure thatcontains the powder bed. One or more position sensors (e.g., heightsensors) can measure the height of the powder bed relative to thesubstrate. The position sensors can be optical sensors. The positionsensors can determine a distance between one or more energy sources(e.g., a laser or an electron beam.) and a surface of the powder. Theone or more sensors may be connected to a control system (e.g., to aprocessor, to a computer).

The system can comprise a first (e.g., FIG. 1, 106) and second (e.g.,FIG. 1, 107) energy source. In some cases, the system can comprisethree, four, five or more energy sources. The system can comprise anarray of energy sources. In some cases, the system can comprise a thirdenergy source. The third energy source can heat at least a fraction of a3D object at any point during formation of a 3D object. Alternatively oradditionally, the powder bed may be heated by a heating membercomprising a lamp, a heating rod, or a radiator (e.g., a panelradiator). In some cases the system can have a single (e.g., first)energy source. An energy source can be a source configured to deliverenergy to an area (e.g., a confined area). An energy source can deliverenergy to the confined area through radiative heat transfer. The energybeam may include a radiation comprising an electromagnetic, chargeparticle, or non-charged particle beam. The energy beam may include aradiation comprising electromagnetic, electron, positron, proton,plasma, or ionic radiation. The electromagnetic beam may comprisemicrowave, infrared, ultraviolet, or visible radiation. The energy beammay include an electromagnetic energy beam, electron beam, particle beamor ion beam, for example. An ion beam may include a cation or an anion.A particle beam may include radicals. The electromagnetic beam maycomprise a laser beam. The energy source may include a laser source. Theenergy source may include an electron gun. The energy source may includean energy source capable of delivering energy to a point or to an area.In some embodiments the energy source can be a laser. In an example alaser can provide light energy at a peak wavelength of at least about100 nanometer (nm), 500 nm, 1000 nm, 1010 nm, 1020 nm, 1030 nm, 1040 nm,1050 nm, 1060 nm, 1070 nm, 1080 nm, 1090 nm, 1100 nm, 1200 nm, 1500 nm,1600 nm, 1700 nm, 1800 nm, 1900 nm, or 2000 nm. In an example a lasercan provide light energy at a peak wavelength of at most about 2000 nm,1900 nm, 1800 nm, 1700 nm, 1600 nm, 1500 nm, 1200 nm, 1100 nm, 1090 nm,1080 nm, 1070 nm, 1060 nm, 1050 nm, 1040 nm, 1030 nm, 1020 nm, 1010 nm,1000 nm, 500 nm, or 100 nm. The laser can provide light energy at a peakwavelength between any of the afore-mentioned peak wavelength values.For example, the laser can provide light energy at a peak wavelengthfrom about 100 nm to about 2000 nm, from about 500 nm to about 1500 nm,or from about 1000 nm to about 1100 nm. An energy beam from the firstand/or second energy source can be incident on, or be directed to, thetop surface of the powder bed (e.g., 101). The energy beam can beincident on a specified area of the powder bed for a specified timeperiod. The powder material in the powder bed can absorb the energy fromthe energy beam and, and as a result, a localized region of the powdermaterial can increase in temperature. The energy beam can be moveablesuch that it can translate relative to the top (i.e., exposed) surfaceof the powder bed. In some instances, the energy source may be movablesuch that it can translate relative to the top surface of the powderbed. The first and optionally the second energy beams and/or sources canbe moved via a galvanometer scanner, a polygon a mechanical stage, orany combination of thereof. The first energy source and/or beam can bemovable with a first scanner (e.g., FIG. 1, 108). The optionally secondenergy source and/or beam can be moveable with a second scanner (e.g.,FIG. 1, 109). The first energy source and the optionally second energysource and/or beam can be translated independently of each other. Insome cases the first and optionally second energy source and/or beam canbe translated at different rates such that the movement of the first orsecond energy source and/or beam is faster compared to the movement ofthe optionally second or first energy source.

Energy (e.g., heat) can be transferred from the powder to a coolingmember (e.g., heat sink FIG. 1, 110). The cooling member can facilitatetransfer of energy away from a least a portion of a powder layer. Insome cases the cooling member can be a thermally conductive plate. Thecooling member can comprise a cleaning mechanism (e.g., cleaningdevice), which removes powder and/or process debris from a surface ofthe cooling member to sustain efficient cooling. Debris can comprisedirt, dust, powder (e.g., that result from heating, melting, evaporationand/or other process transitions), or hardened material that did notform a part of the 3D object. In some cases the cleaning mechanism cancomprise a stationary rotating rod, roll, brush, rake, spatula, or bladethat rotates when the heat sinks moves in a direction adjacent to thebase. The cleaning mechanism may comprise a vertical cross section(e.g., side cross section) of a circle, triangle, square, pentagon,hexagon, octagon, or any other polygon. The vertical cross section maybe of an amorphous shape. In some cases the cleaning mechanism rotateswhen the cooling member moves in a direction that is not lateral. Insome cases the cleaning mechanism rotates without movement of thecooling member. In some cases, the cooling member comprises at least onesurface that is coated with a layer that prevents powder and/or debrisfrom attaching to the at least one surface (e.g., an anti-stick layer).

One or more temperature sensors can sense the temperature of the coolingmember. The temperature sensor can comprise thermocouple, thermistor,pyrometer, thermometer (e.g., resistance thermometer), or a silicon bandgap temperature sensor. The cooling member can comprise two or morethermally conductive plates. The cooling member can be made from athermally conductive material, for example a metal or metal alloy. Thecooling member can comprise copper or aluminum. The cooling member(e.g., heat sink) can comprise a material that conducts heatefficiently. The efficient heat conductivity may be at least about 20Watts per meters times degrees Kelvin (W/mK), 50 W/mK, 100 W/mK, 150W/mK, 200 W/mK, 205 W/mK, 300 W/mK, 350 W/mK, 400 W/mK, 450 W/mK, 500W/mK, 550 W/mK, 600 W/mK, 700 W/mK, 800 W/mK, 900 W/mK, or 1000 W/mK.The efficient heat conductivity may of any value between theaforementioned values. For example, the efficient heat conductivity maybe from about 400 W/mK to about 1000 W/mK, or from about 20 W/mK toabout 500 W/mK. The heat sink can comprise an elemental metal or a metalalloy. The heat sink can comprise elemental metal, metal alloy, ceramic,an allotrope of elemental carbon, or a polymer. The heat sink cancomprise stone, zeolite, clay or glass. The heat sink (e.g., 110) can beplaced above the top surface of the powder bed (e.g., 101). The heatsink can be placed below the powder bed, or to the side of the surfaceof the powder bed. In some cases the heat sink can contact a surface ofthe powder bed. The heat sink can just touch the surface of the powderbed. The heat sink can apply a compressive force to the exposed surfaceof the powder bed. In some cases the heat sink can extend past the edgesof the top surface of the powder bed. In some cases the heat sink canextend up to the edges of the top surface of the powder bed. In somecases the heat sink can extend to the edges of the top surface of thepowder bed. The heat sink can facilitate the transfer of energy from atleast a portion of a powder layer without substantially changing andinitial configuration of the powder material in the powder layer. Insome cases the powder layer can comprise a fully or partially formed 3Dobject. The heat sink can facilitate the transfer of energy from atleast a portion of a powder layer without substantially altering theposition of the printed 3D object (or a part thereof) by any of theposition alteration values disclosed herein.

The cooling member may be a heat transfer member that enables heating,cooling or maintaining the temperature of the powder bed or of the 3Dobject being formed in the powder bed. In some examples, the heattransfer member is a cooling member that enables the transfer of energyout of the powder bed. The heat transfer member can enable the transferof energy to the powder bed.

Heat can be transferred from the powder bed to the heat sink through anyone or combination of heat transfer mechanisms (e.g., conduction,natural convection, forced convection, and radiation). The heat sink canbe solid, liquid or semi-solid. In some examples, the heat sink issolid. The heat sink may comprise a gas. Alternatively, the heat sinkcan comprise one or more openings (e.g., FIG. 2, 205). The openings canbe arranged in a pattern or randomly. The openings can be arranged in astriped pattern or a chessboard pattern. In some cases, powder removalopenings (e.g., suction nozzles) can be adjacent to the openings. In anexample, the heat sink can be a plate. An example of a heat sink isshown in FIG. 2. In the example shown in FIG. 2 the heat sink 201 is adistance d from the surface of the powder bed 202, which constitutes agap. The gap can be adjustable or fixed. The heat sink can be controlledby a control system (e.g., a processor). The gap can be adjusted by thecontrol system based on a melting energy per unit area that is suitableto transform the powder bed or a portion thereof. A layer of gas (e.g.,203) can be provided between the heat sink and the surface of the powderbed. The heat sink can be thermally coupled to the powder bed throughthe layer of gas. The layer of gas can comprise ambient gas (e.g., air),argon, nitrogen, helium, neon, krypton, xenon, hydrogen, carbonmonoxide, carbon dioxide, or oxygen. In some cases, the layer of gas canbe chosen to achieve a desired heat transfer property between the topsurface of the powder bed and the heat sink. A distance sensor canmeasure the distance of the gas gap. The distance sensor may comprise anoptical sensor, a capacitance sensor, or both an optical sensor and acapacitance sensor. In an example, a gas with high thermal conductivitycan be chosen. The gas gap can be an environment between the heat sinkand an exposed surface of the powder bed. The size of the gap may becontrolled. In some cases, rotational gas flow currents can be generatedin the gap. The currents can increase, or cause, convective heattransfer between the powder bed and the heat sink. In some cases, thecurrents can be driven by movement of the heat sink with periodic wedgespresent along the heat sink to direct the currents to the powder bed.The wedges can be periodically spaced along a surface of the heat sinkwith a spacing distance from about 1 μm to about 100 mm, or from about10 μm to about 10 mm. Alternatively or additionally, a convectivecurrent can be generated in the gas gap by forcing gas flow in the gap.The gas flow can be forced by a first array or matrix of nozzlesembedded in the heat sink (e.g., in the surface of the heat sink). Thenozzles can be oriented towards a surface of the powder bed and canallow gas to flow in to the gap (e.g., via release of a pressurizedgas). A second array or matrix of nozzles can remove the gas introducedby the first array or matrix of nozzles to create gas flow (e.g., viavacuum mechanism).

In some cases the heat sink can comprise a heat exchanger (e.g., 204).The heat exchanger (e.g., thermostat) can be configured to maintain thetemperature of the heat sink at a constant target temperature. In somecases the target temperature can be higher than, lower than, orsubstantially equivalent to the ambient temperature. The heat exchangercan circulate a cooling fluid through a plumbing system (e.g., pipe orcoil) embedded in the heat sink. The cooling fluid can be configured toabsorb heat from the heat sink through any one or combination of heattransfer mechanisms (e.g., conduction, natural convection, forcedconvection, and radiation). The cooling fluid can be water, oil, or arefrigerant (e.g., R34a). In some examples, the cooling member is notembedded within the powder bed (e.g., in a form of pipes).

The cooling member can cool a surface of the powder through mechanicalcontact. The cooling member can contact a surface of the powder bed formost about 1 second (s), 5 s, 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s,80 s, 90 s, 100 s, 110 s, 120 s, 130 s, 140 s, 150 s, 160 s, 170 s, 180s, 190 s, 200 s, 210 s, 220 s, 230 s, 240 s, 250 s, 260 s, 270 s, 280 s,290 s, 300 s, 10 minutes, 15 minutes, 30 minutes, 1 hour, 3 hours, 6hours, 12 hours, 1 day, or less. The cooling member can contact asurface of the powder bed for at least about 1 second (s), 5 s, 10 s, 20s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 120 s, 130 s,140 s, 150 s, 160 s, 170 s, 180 s, 190 s, 200 s, 210 s, 220 s, 230 s,240 s, 250 s, 260 s, 270 s, 280 s, 290 s, 300 s, 10 minutes, 15 minutes,30 minutes, 1 hour, 3 hours, 6 hours, 12 hours, 1 day, or more. Thecooling member can contact a surface of the powder bed for at timebetween any of the aforementioned time periods. For example the coolingmember can contact a surface of the powder bed for at time period fromabout 1 s to about 15 min, from about 1 s to about 10 min, from about 1s to about 5 min, from about 1 s to about 1 min, or from about 1 s toabout 30 s. The cooling member can be a plate that contacts the surfaceof the powder bed along a planar dimension. In some cases the coolingmember can be a one or more cylinder that roll along the surface of thepowder. Alternatively the cooling member can be a belt that runs alongthe surface of the powder. The cooling member can comprise spikes,ridges, or other protrusions features configured to penetrate into thepowder to enhance cooling surface area and depth. The protrudingfeatures may be bendable (e.g., soft) or non-bendable (e.g., stiff).

In some instances the cooling member does not reside within the powdermaterial. In other examples, the cooling member may reside within thepowder material. The cooling member can be a duct or a pipe.

In some instances, the cooling member is not a plate. The cooling membercan be a cooled powder layer. The cooled powder layer can act as a heatsink. The cooled powder layer can be integrated with a raking memberthat provides and/or moves the powder material adjacent to the baseand/or another powder layer. A raking member can provide a layer ofcooled powder with a thickness of at least about 0.5 mm, 1 mm, 5 mm, 10mm, 15 mm, 20 mm, 25 mm, or 30 mm adjacent to a first powder layer. Araking member can provide a layer of cooled powder with a thickness ofat most about 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mmadjacent to a first powder layer. Heat (e.g., thermal energy) from afirst powder layer can be removed by transfer from the first powderlayer to the cooled powder layer. The cooled powder layer can beprovided at a temperature of at most about −40° C., −20° C., −10° C., 0°C., 10° C., 20° C., 25° C., 30° C., 40° C., 50° C., 60° C., 70° C., 80°C., 90° C., 100° C., 200° C., 300° C., 400° C., or 500° C. The cooledpowder layer can be provided at a temperature of at least about −40° C.,−20° C., −10° C., 0° C., 10° C., 20° C., 25° C., 30° C., 40° C., 50° C.,60° C., 70° C., 80° C., 90° C., 100° C., 200° C., 300° C., 400° C., or500° C. The cooled powder layer can be provided at a temperature betweenthe above listed temperature values. After the heat transfer hasoccurred most of the layer of cooled powder can be removed such that theremaining layer has a thickness of at most about 500 μm, 250 μm, 100 μm,50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 5μm, 1 μm, or 0.5 μm. The remaining cooled powder can be exposed toeither or both of the first and the optionally second (or additional)energy source to form at least a portion of a 3D object.

FIG. 9 depicts another example of a system that can be used to generatea 3D object using a 3D printing process. The system 900 shown in FIG. 9can be similar to the system shown in FIG. 1. The system 900 shown inFIG. 9 can comprise at least some of the components included in thesystem shown in FIG. 1. The system 900 shown in FIG. 9 can compriseadditional components that are not included in FIG. 1.

The system 900 can include an enclosure (e.g., a chamber 901). At leasta fraction of the components in the system 900 can be enclosed in thechamber 901. At least a fraction of the chamber 901 can be filled with agas to create a gaseous environment. The gas can be an inert gas (e.g.,Argon, Neon, or Helium). The chamber can be filled with another gas ormixture of gases. The gas can be a non-reactive gas (e.g., an inertgas). The gaseous environment can comprise argon, nitrogen, helium,neon, krypton, xenon, hydrogen, carbon monoxide, or carbon dioxide. Thepressure in the chamber can be at least 10⁻⁷ Torr, 10⁻⁶ Torr, 10⁻⁵ Torr,10⁻⁴ Torr, 10⁻³ Torr, 10⁻² Torr, 10⁻¹ Torr, 1 Torr, 10 Torr, 100 Torr, 1bar, 2 bar, 3 bar, 4 bar, 5 bar, 10 bar, 20 bar, 30 bar, 40 bar, 50 bar,100 bar, 200 bar, 300 bar, 400 bar, 500 bar, 1000 bar, or more. Thepressure in the chamber can be at least 100 Torr, 200 Torr, 300 Torr,400 Torr, 500 Torr, 600 Torr, 700 Torr, 720 Torr, 740 Torr, 750 Torr,760 Torr, 900 Torr, 1000 Torr, 1100 Torr, 1200 Torr. The pressure in thechamber can be at most 10⁻⁷ Torr, 10⁻⁶ Torr, 10⁻⁵ Torr, or 10⁻⁴ Torr,10⁻³ Torr, 10⁻² Torr, 10⁻¹ Torr, 1 Torr, 10 Torr, 100 Torr, 200 Torr,300 Torr, 400 Torr, 500 Torr, 600 Torr, 700 Torr, 720 Torr, 740 Torr,750 Torr, 760 Torr, 900 Torr, 1000 Torr, 1100 Torr, or 1200 Torr. Thepressure in the chamber can be at a range between any of theaforementioned pressure values. For example, the pressure may be fromabout 10⁻⁷ Torr to about 1200 Torr, from about 10⁻⁷ Torr to about 1Torr, from about 1 Torr to about 1200 Torr, or from about 10⁻² Torr toabout 10 Torr. In some cases the pressure in the chamber can be standardatmospheric pressure. In some examples, the chamber 901 can be undervacuum pressure.

The chamber can comprise two or more gaseous layers. The gaseous layerscan be separated by molecular weight or density such that a first gaswith a first molecular weight or density is located in a first region(e.g., 903) of the chamber and a second gas with a second molecularweight or density that is smaller than the first molecular weight ordensity is located in a second region (e.g., 902) of the chamber. Thegaseous layers can be separated by temperature. The first gas can be ina lower region of the chamber relative to the second gas. The second gasand the first gas can be in adjacent locations. The second gas can be ontop of, over, and/or above the first gas. In some cases the first gascan be argon and the second gas can be helium. The molecular weight ordensity of the first gas can be at least about 1.5*, 2*, 3*, 4*, 5*,10*, 15*, 20*, 25*, 30*, 35*, 40*, 50*, 55*, 60*, 70*, 75*, 80*, 90*,100*, 200*, 300*, 400*, or 500* larger or greater than the molecularweight or density of the second gas. “*” used herein designates themathematical operation “times.” The molecular weight of the first gascan be higher than the molecular weight of air. The molecular weight ordensity of the first gas can be higher than the molecular weight ordensity of oxygen gas (e.g., O₂). The molecular weight or density of thefirst gas can be higher than the molecular weight or density of nitrogengas (e.g., N₂). At times, the molecular weight or density of the firstgas may be lower than that of oxygen gas or nitrogen gas.

The first gas with the relatively higher molecular weight or density canfill a region of the system (e.g., 903) where at least a fraction of thepowder is stored. The second gas with the relatively lower molecularweight or density can fill a region of the system (e.g., 902) where the3D object is formed. The region where the 3D object is formed cancomprise a powder layer that is receiving energy in a predeterminedpattern to form at least a fraction of the 3D object; the powder layercan be supported on a substrate (e.g., 904). The substrate can have acircular, rectangular, square, or irregularly shaped cross-section. Thesubstrate may comprise a base disposed above the substrate. Thesubstrate may comprise a base disposed between the substrate and apowder layer (or a space to be occupied by a powder layer). The regionwhere the 3D object is formed can further comprise a leveling mechanism(e.g., a roll, brush, rake, spatula or blade) configured to move and/orlevel powder material along the powder layer. The leveling mechanism maycomprise a vertical cross section (e.g., side cross section) of acircle, triangle, square, pentagon, hexagon, octagon, or any otherpolygon, or partial shape or combination of shapes thereof. The levelingmechanism may comprise a vertical cross section (e.g., side crosssection) of an amorphous shape. The leveling mechanism may comprise oneor more blades. In some examples, the leveling mechanism comprises ablade with two mirroring sides, or two blades attached to form twomirroring blades. Such mirroring arrangement may ensure a similar actionwhen the leveling mechanism is traveling in one side and in the oppositeside. A thermal control unit (e.g., a cooling member such as a heatsink, a cooling plate, a heating plate, or a thermostat) can be providedinside of the region where the 3D object is formed or adjacent to theregion where the 3D object is formed. The thermal control unit can beprovided outside of the region where the 3D object is formed (e.g., at apredetermined distance). In some cases, the thermal control unit canform at least one section of a boundary region where the 3D object isformed (e.g., the container accommodating the powder bed).

The concentration of oxygen in the chamber can be minimized. Theconcentration of oxygen or humidity in the chamber can be maintainedbelow a predetermined threshold value. For example, the gas compositionof the chamber can contain a level of oxygen or humidity that is at mostabout 100 parts per billion (ppb), 10 ppb, 1 ppb, 0.1 ppb, 0.01 ppb,0.001 ppb, 100 parts per million (ppm), 10 ppm, 1 ppm, 0.1 ppm, 0.01ppm, or 0.001 ppm. The gas composition of the chamber can contain anoxygen or humidity level between any of the aforementioned values. Forexample, the gas composition of the chamber can contain a level ofoxygen or humidity from about 100 ppb to about 0.001 ppm, from about 1ppb to about 0.01 ppm, or from about 1 ppm to about 0.1 ppm. In somecases, the chamber can be opened at the completion of a formation of a3D object. When the chamber is opened, ambient air containing oxygenand/or humidity can enter the chamber. Exposure of one or morecomponents inside of the chamber to air can be reduced by, for example,flowing an inert gas while the chamber is open (e.g., to prevent entryof ambient air), or by flowing a heavy gas (e.g., argon) that rests onthe surface of the powder bed. In some cases, components that absorboxygen and/or water on to their surface(s) can be sealed while thechamber is open.

The chamber can be configured such that gas inside of the chamber has arelatively low leak rate from the chamber to an environment outside ofthe chamber. In some cases the leak rate can be at most about 100milliTorr/minute (mTorr/min), 50 mTorr/min, 25 mTorr/min, 15 mTorr/min,10 mTorr/min, 5 mTorr/min, 1 mTorr/min, 0.5 mTorr/min, 0.1 mTorr/min,0.05 mTorr/min, 0.01 mTorr/min, 0.005 mTorr/min, 0.001 mTorr/min, 0.0005mTorr/min, or 0.0001 mTorr/min. The leak rate may be between any of theaforementioned leak rates (e.g., from about 0.0001 mTorr/min to about100 mTorr/min, from about 1 mTorr/min to about 100 mTorr/min, or fromabout 1 mTorr/min to about 100 mTorr/min). The chamber (e.g., 901) canbe sealed such that the leak rate of gas from inside the chamber to anenvironment outside of the chamber is low. The seals can compriseO-rings, rubber seals, metal seals, load-locks, or bellows on a piston.In some cases the chamber can have a controller configured to detectleaks above a specified leak rate (e.g., by using a sensor). The sensormay be coupled to a controller. In some instances, the controller isable to identify a leak by detecting a decrease in pressure in side ofthe chamber over a given time interval.

Powder can be dispensed on to the substrate (e.g., 904) to form a 3Dobject from the powder material. The powder can be dispensed from apowder dispensing mechanism (e.g., 905 such as a powder dispenser). Thepowder dispensing mechanism can be adjacent to the powder bed. Thepowder dispensing mechanism may span the entire width of the powder bed,entire length of the powder bed, or a portion of the powder bed. Thepowder dispensing mechanism may comprise an array of powder deliverycomponents (e.g., array of powder dispensers). The array of powderdelivery components may be spaced apart evenly or unevenly. The array ofpowder dispensing components may be spaced apart by at most 0.1 mm, 0.3mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm. The array of powderdelivery components may be spaced apart by at least 0.1 mm, 0.3 mm, 0.5mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm. The array of powderdelivery components (e.g., members) may be spaced apart between any ofthe afore-mentioned spaces of the leveling members (e.g., from about 0.1mm to about 5 mm, from about 0.1 mm to about 2 mm, from about 1.5 mm toabout 5 mm). The leveling mechanism may be coupled to or may be a partof the powder dispensing mechanism. The leveling mechanism may compactthe powder within the layer of powder material. In some instances, theleveling mechanism substantially does not compact the powder in thelayer of powder material.

FIGS. 13A-D schematically depict vertical side cross sections of variousmechanisms for dispensing the powder material. FIG. 13A depicts a powderdispenser 1303 situated above the surface 1310 moving in the direction1306. FIG. 13B depicts a powder dispenser 1311 situated above thesurface 1317 moving in the direction 1314. FIG. 13C depicts a powderdispenser 1318 situated above the surface 1325 moving in the direction1321. FIG. 13D depicts a powder dispenser 1326 situated above thesurface 1333 moving in the direction 1329.

The powder dispensing mechanism may be coupled to or may be a part of apowder removal mechanism (e.g., a powder removal member). The powderremoval member may be referred herein as a powder removal system. Forexample, FIG. 25C shows a powder dispensing mechanism that is integratedwith the powder removal system (e.g., 2531). In that system (i.e.,mechanism), the powder delivery components (e.g., 2533) are spacedapart, and are integrated with the powder removal mechanism components(e.g., 2532). The integration of the components may form a pattern, ormay be separated into two groups each of which containing one type ofcomponent, or may be randomly situated. The one or more powder exitports and one or more vacuum entry ports may be arranged in a pattern(e.g., sequentially), grouped together, or at random. The one or morepowder exit ports and one or more vacuum entry ports operatesequentially, simultaneously, in concert, or separate from each other.

The powder dispensing mechanism may be integrated with both the powderremoval system and the powder leveling system. FIG. 24 shows an examplefor an integration of the three systems. As the system moves along thedirection 2401 above a powder bed 2409, the powder dispensing mechanism2406 deposits powder material 2407. That delivery system is coupled(e.g., through 2403) to a powder leveling system 2405 that includes aleveling component 2408 (e.g., a knife) and levels the deposited powdermaterial 2411. The powder leveling system is coupled (e.g., though 2402)to a powder removal system 2404 that removes the deposited and leveledpowder material without contacting the top surface of the leveled powderlayer 2411. The removal may utilize negative pressure (e.g., vacuum) asexemplified in FIG. 24, 2421.

FIGS. 25A-C schematically depict bottom views of various mechanisms forremoving the powder material. FIG. 25A schematically depicts a powderremoval member 2511 having a powder entrance opening port 2512. FIG. 25Bschematically depicts a powder removal member 2521 having manifolds(e.g., 2523) of multiple powder entrance opening ports (e.g., 2522).FIG. 25C schematically depicts an integrated powder dispensing-removalmember 2531 having powder entrance opening ports (e.g., 2532), andpowder exit opening ports (e.g., 2533).

The powder removal system can be oriented above, below, and/or to theside of the substrate (e.g., the substrate, the base or the powder bed).The powder removal system may rotate at an axis. The axis of rotationmay be normal to the direction in which powder enters the powder removalsystem. In some examples, the powder removal system may not berotatable. The powder removal system may be translatable horizontally,vertically or at an angle. The powder removal system may comprise apowder entrance opening and a powder exit opening port. The powderentrance and powder exit may be the same opening. The powder entranceand powder exit may be different openings. The powder entrance andpowder exit may be spatially separated. The spatial separation may be onthe external surface of the powder removal system. The powder entranceand powder exit may be connected. The powder entrance and powder exitmay be connected within the powder removal system. The connection may bean internal cavity within the powder removal system. For example, FIG.24 schematically shows a powder removal system 2404 having a nozzle 2413opening though which the powder enters. The nozzle may comprise a singleopening or a multiplicity of openings. The multiplicity of openings maybe aggregated (e.g., in a nozzle). FIG. 24 schematically depicts anozzle having three openings 2415, 2417, and 2419. The multiplicity ofopenings may be vertically leveled (e.g., aligned). In some instances,at least one opening within the multiplicity of openings may bevertically misaligned. In some examples, none of the openings may resideon the same vertical level. FIG. 24 exemplifies three openings that eachresides on a different vertical level (e.g., 2416, 2418, and 2420).

The powder material may travel from the powder entry to the powder exit,though the internal cavity. For example, FIG. 24 shows a powder materialthat enters the openings 2415, 2417, and 2419 and travels through theinternal cavity 2424 to an exit 2423. In some cases, the powder materialcan be dispensed from a top powder removal system that is located abovethe powder bed. The top powder removal system can remove powder from thepowder bed from a position above the powder bed at a predetermined time,rate, location, removal scheme, or any combination thereof. In someexamples, the powder removal system contacts the powder bed (e.g., theexposed surface of the powder bed). In some examples, the powder removalsystem does not contact the powder bed (e.g., the exposed surface of thepowder bed). The powder removal system may be separated from the topsurface of the powder bed (e.g., the exposed surface of the powder bed)by a gap. The gap may be adjustable. The vertical distance of the gapfrom the exposed surface of the powder bed may be at least about 0.5 mm,1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 20 mm, 30mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm. The verticaldistance of the gap from the exposed surface of the powder bed may be atmost about 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm,10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100mm. The vertical distance of the gap from the exposed surface of thepowder bed may be any value between the aforementioned values (e.g.,from about 0.5 mm to about 100 mm, from about 0.5 mm to about 60 mm, orfrom about 40 mm to about 100 mm). The top powder removal system mayhave at least one opening. The size of the opening, the shape of theopening, the timing and the duration of the opening may be controlled bya controller. The top-dispense powder dispenser can remove powder from aheight that is higher compared to a surface of the top surface of thepowder bed. The powder dispensing mechanism can remove powder from atleast a fraction of the powder bed. The powder removal system maycomprise a force that causes the powder material to travel from thepowder bed towards the interior of the powder removal system. The powderremoval system may comprise negative pressure (e.g., vacuum),electrostatic force, electric force, magnetic force or physical force.The powder removal system may comprise positive pressure (e.g., a gas)that causes the powder to leave the powder bed and travel into theopenings of the powder removal pressure. The gas may comprise any gasdisclosed herein. The gas may aid in fluidizing the powder material thatremains in the powder bed. The removed powder material may be recycledand re-applied into the powder bed by the powder dispensing system. Thepowder may be continuously recycled though the operation of the powderremoval system. The powder may be recycled after each layer of materialhas been deposited (e.g., and leveled). The powder may be recycled afterseveral layers of material have been deposited (e.g., and leveled). Thepowder may be recycled after each 3D object has been printed.

Any of the powder removal systems described herein can comprise areservoir of powder and/or a mechanism configured to deliver the powderfrom the reservoir to the powder dispensing system. The powder in thereservoir can be treated. The treatment may include heating, cooling,maintaining a predetermined temperature, sieving, filtering, orfluidizing (e.g., with a gas). A leveling mechanism (e.g., FIG. 11,1103; FIGS. 12A-F, 1202, 1207, 1212, 1217, 1222, or 1227; or FIG. 15,1503; such as a rake, roll, brush, spatula or blade) can be synchronizedwith the powder removing system.

The powder removal mechanism may have an opening though which powderenters the suction device from the top surface of the powder bed (e.g.,FIG. 23, 2312). The entrance chamber to which the powder enters thesuction device (e.g., FIG. 23, 2305) can be of any shape. The entrancechamber can be a tube (e.g., flexible or rigid). The entrance chambercan be a funnel. The entrance chamber can have a rectangular crosssection or a conical cross section. The entrance chamber can have anamorphic shape. The powder removal mechanism (e.g., suction device) mayinclude one or more suction nozzles. The suction nozzle may comprise anyof the nozzles described herein. The nozzles may comprise of a singleopening or a multiplicity of openings as described herein. The openingsmay be vertically leveled or not leveled). The openings may bevertically aligned, or misaligned. In some examples, at least two of themultiplicity of openings may be misaligned. The multiplicity suctionnozzles may be aligned at the same height relative to the substrate(e.g., FIG. 23, 2311), or at different heights (e.g., vertical height).The different height nozzles may form a pattern, or may be randomlysituated in the suction device. The nozzles may be of one type, or ofdifferent types. The powder removal mechanism (e.g., suction device) maycomprise a curved surface, for example adjacent to the side of a nozzle.Powder material that enters though the nozzle may be collected at thecurved surface. The nozzle may comprise a cone. The cone may be aconverging cone or a diverging cone. The powder removal mechanism (e.g.,suction device) may comprise a powder reservoir. The powder that entersthe powder removal mechanism may at times enter the powder removalmechanism reservoir. The reservoir can be emptied after each powderlayer has been leveled, when it is filled up, at the end of the buildcycle, or at a whim. The reservoir can be continuously emptied duringthe operation of the powder removal mechanism. FIG. 23, 2307 shows anexample of a powder reservoir within the suction device. At times, thepowder removal mechanism does not have a reservoir. At times, the powderremoval mechanism constitutes a powder removal (e.g., a suction) channelthat leads to an external reservoir. The powder removal mechanism maycomprise an internal reservoir.

The powder removal mechanism may travel laterally before a levelingmember (e.g., a roller) relative to the direction of movement. Thepowder removal mechanism may travel laterally after the leveling member,relative to the direction of movement. The powder removal mechanism maybe part of the leveling member. The powder removal mechanism may be theleveling member. The powder removal mechanism may be connected to theleveling member (e.g., the roller). The powder removal mechanism may bedisconnected from the leveling member. The powder removal mechanism maycomprise an array of powder entries (e.g., suction devices or nozzles).The array of powder entries (e.g., nozzle, powder openings, or anaggregate of openings) may be spaced apart evenly or unevenly. The arrayof powder entries may be spaced apart at most about 0.1 mm, 0.3 mm, 0.5mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm. The array of le powderentries may be spaced apart at least about 0.1 mm, 0.3 mm, 0.5 mm, 1 mm,1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm. The array of powder entries may bespaced apart between any of the afore-mentioned spaces of the levelingmembers (e.g., from about 0.1 mm to about 5 mm, from about 0.1 mm toabout 2 mm, from about 1.5 mm to about 5 mm).

A controller may control the powder removal system. The controller maycontrol the speed (velocity) of lateral movement of the powder removalsystem. The controller may control the level of pressure (e.g., vacuumor positive pressure) in the powder removal system. The pressure level(e.g., vacuum or positive pressure) may be constant or varied. Thepressure level may be turned on and off manually or by the controller.The pressure level may be less than about 1 atmosphere pressure (760Torr). The pressure level may be any pressure level disclosed herein.The controller may control the amount of force exerted or residingwithin the powder removal system. For example, the controller maycontrol the amount of magnetic force, electric force, electrostaticforce or physical force exerted by the powder removal system. Thecontroller may control if and when the aforementioned forces areexerted.

The powder dispensing mechanism can be oriented above, and/or belowpowder bed (or the container thereof). The powder dispensing mechanismmay rotate at an axis. The axis of rotation may be normal to thedirection in which powder exits the powder dispensing mechanism. In someexamples, the powder dispensing mechanism may not be rotatable. Thepowder dispensing mechanism may translatable horizontally, vertically orat an angle. The axis of rotation of the powder dispensing mechanism maybe normal or parallel to the direction of translation. The powderdispensing mechanism may comprise a powder entrance opening and a powderexit opening port. The powder entrance and powder exit may be the sameopening. The powder entrance and powder exit may be different openings.The powder entrance and powder exit may be spatially separated. Thespatial separation may be on the external surface of the powderdispensing mechanism. The powder entrance and powder exit may beconnected. The powder entrance and powder exit may be connected withinthe powder dispensing mechanism. The connection may be an internalcavity within the powder dispensing mechanism. The powder material maytravel from the powder entry to the powder exit, though the internalcavity. In some cases, the powder material can be dispensed from atop-dispense powder dispenser that is located above the substrate. Thetop-dispense powder dispenser can release powder on to the substratefrom a position above the substrate at a predetermined time, rate,location, dispensing scheme, or any combination thereof. Thetop-dispense powder dispenser may have at least one opening. The size ofthe opening, the shape of the opening, the timing and the duration ofthe opening may be controlled by a controller. The top-dispense powderdispenser can release powder on to the substrate from a height that ishigher compared to a surface of the substrate. The powder dispensingmechanism can dispense powder onto at least a fraction of the substrate904. The powder dispensing mechanism may comprise openings though whichgas can travel though. The gas may comprise any gas disclosed herein.The gas may aid in fluidizing the powder material that resides in thepowder dispenser reservoir, or that is dispensed from the powderdispensing mechanism.

The powder dispensing mechanism may comprise a chamber through which gasflows. The powder dispensing mechanism chamber may comprise a singlecompartment or a multiplicity of compartments. The multiplicity ofcompartments may have identical or different vertical cross sections,horizontal cross sections, surface areas, or volumes. The walls of thecompartments may comprise identical or different materials. Themultiplicity of compartments may be connected such that gas may travel(flow) from one compartment to another (termed herein “flowablyconnected”). The multiplicity of compartments may be connected such thatpowder material that was picked up by the gas (e.g., airborne powdermaterial) may travel (flow) from one compartment to another. FIG. 27Cshows examples of a powder dispensing mechanism having threecompartments of various vertical cross sections (2738, 2739, and 2740)that are flowably connected as illustrated by the gas flow 2733 withinthe internal cavity of the powder dispensing mechanism. The powderdispensing mechanism chamber may comprise a gas entrance, gas exit,powder entrance, and powder exit. In some examples, the powderdispensing mechanism chamber may be comprised of two powder exits. Thegas entrance and the powder material entrance may be the same ordifferent entrances. The gas exit and the powder material exit may bethe same or different entrances. The portion that faces the substrate,the base, or the exposed surface of the powder bed is designated hereinas the bottom portion. The portion that faces away from the substrate,the base, or the exposed surface of the powder bed is designated hereinas the top portion. The portion that is different from the top or thebottom portion is designated herein as the side portion. In someexamples, a powder exit faces the substrate, the base, or the exposedsurface of the powder bed. In some examples, a powder exit resides atthe bottom of the powder dispensing system. The bottom exit may comprisea mesh, slit, hole, slanted baffle, shingle, ramp, slanted plane or anycombination thereof. For example, FIG. 27A shows an example of a mesh2715 at the bottom of the powder dispensing mechanism; FIG. 27B shows anexample of a combination of a mesh 2725 and slanted baffles (e.g.,2726); and FIG. 27C shows an example of slanted baffles (e.g., 2736) atthe bottom of the powder dispensing mechanism. The mesh may have anymesh values disclosed herein. In some examples, the mesh can comprisehole sizes of at least about 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm,700 μm, 800 μm, 900 μm, or 1000 μm. The mesh can comprise hole sizes ofat most about 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900μm, or 1000 μm. The mesh can comprise hole sizes between any of the holesizes disclosed herein. For example, the mesh can comprise hole sizesfrom about 5 μm to about 1000 μm, from about 5 μm to about 500 μm, fromabout 400 μm to about 1000 μm, or from about 200 μm to about 800 μm.

The chamber in which the bottom opening is situated can be symmetricalwith respect to the incoming gas (e.g., FIG. 27A), or unsymmetrical(e.g., FIG. 27D). The direction of the gas flow can coincide with thedirection of lateral movement of the powder dispensing system, notcoincide, or flow opposite thereto. For example, FIG. 27A schematicallyshows a powder dispensing mechanism where the direction of the gas flow2713 coincides with the direction of lateral movement of the powderdispensing system 2712. The powder can be disposed away from the bottomopening. The powder can be supplied from a reservoir. The supply of thepowder can be from the top of the powder dispensing chamber, from thebottom, or from the side. For example, FIG. 27A shows a powder reservoir2719 that delivers powder from the bottom of the powder dispenserchamber. The powder can be elevated by an elevation mechanism. Theelevation mechanism can comprise a conveyor or an elevator. Theelevation mechanism can comprise a mechanical lift. The elevationmechanism can comprise an escalator, elevator, conveyor, lift, ram,plunger, auger screw, or Archimedes screw. The elevation mechanism cancomprise a transportation system that is assisted by gas (e.g.,pressurized gas), electricity, heat (e.g., steam), or gravity (e.g.,weights). The conveyor may be coarse; the conveyor may comprise ledges,protrusions, or depressions. The protrusions or depressions may trappowder material to be conveyed to the chamber interior where gas flowsfrom one side to the other. FIG. 27B shows a powder reservoir 2729 thatdelivers powder from the top of the powder dispenser chamber. The powderdelivery can include any other top-powder delivery methods describedherein.

The gas may travel within the powder dispensing mechanism chamber at avelocity. The velocity may be varied. The velocity may be variable orconstant. The velocity may be at least about 0.001 Mach, 0.03 Mach,0.005 Mach, 0.07 Mach, 0.01 Mach, 0.03 Mach, 0.05 Mach, 0.07 Mach, 0.1Mach, 0.3 Mach, 0.5 Mach, 0.7 Mach, or 1 Mach. The velocity may bevaried. The velocity may be variable or constant. The velocity may be atmost about 0.001 Mach, 0.03 Mach, 0.005 Mach, 0.07 Mach, 0.01 Mach, 0.03Mach, 0.05 Mach, 0.07 Mach, 0.1 Mach, 0.3 Mach, 0.5 Mach, 0.7 Mach, or 1Mach. The velocity may be between any of the aforementioned velocityvalues. For example, the velocity may be from about 0.01 Mach to about0.7 Mach, from about 0.005 Mach to about 0.01 Mach, from about 0.05 Machto about 0.9 Mach, from about 0.007 Mach to about 0.5 Mach, or fromabout 0.001 Mach to about 1 Mach. Mach as used herein refers to Machnumber that represents the ratio of flow velocity past a boundary to thelocal speed of sound.

Any of the powder dispensing mechanisms described herein (e.g., FIG. 9,905; FIG. 13C, 1319; or FIG. 15, 1508) can comprise a reservoir ofpowder and a mechanism configured to deliver the powder from thereservoir to the powder bed. Powder in the reservoir can be preheated,cooled, be at an ambient temperature or maintained at a predeterminedtemperature. A leveling mechanism (e.g., FIG. 11, 1103; FIG. 12A-F,1202, 1207, 1212, 1217, 1222, or 1227; or FIG. 15, 1503; such as a rake,roll, brush, spatula or blade) can be synchronized with the powderdispenser.

A controller may control the powder dispensing mechanism. The controllermay control the speed (velocity) of lateral movement of the powderdispensing mechanism. When applicable, the controller may control gasvelocity in the powder dispensing system. The controller may controltype of gas that travels within the powder dispensing system. Thecontroller may control the amount of powder material released by thepowder dispensing system. The controller may control the position inwhich the powder is deposited in the powder bed. The controller maycontrol the radius of powder deposition in the powder bed. Thecontroller may control the rate of powder deposition in the powder bed.The controller may control the vertical height of the powder dispensingsystem. The controller may control the gap between the bottom of thepowder dispensing system and the top surface of the powder bed. Thecontroller may control the gap between the opening of the powderdispensing system and the slanted plane that is included in the powderdispensing system. The controller may control the angle (theta) of thatslanted plane. The controller may control the rate of vibration of thevibrators that are part of the powder dispensing system (e.g., FIG. 28,2836). For example, the controller may control the rate of vibration ofthe powder in the powder reservoir within the powder dispensing system.

The layer dispensing mechanism can dispense the powder material, level,distribute, spread, and/or remove the powder in the powder bed. Theleveling mechanism can level, distribute and/or spread the powder in thepowder bed. The leveling mechanism can reduce the height of the powderlayer deposited (e.g., on the top of the powder bed or within thecontainer accommodating the powder bed). The leveling mechanism canrelocate, cut, shear or scrape off a top portion of the powder layer. Insome examples, the leveling mechanism can remove (e.g., evacuate) thepowder material. In some examples, the removal of the powder materialcan be performed by a separate mechanism that is connected to the powderleveling mechanism (e.g., powder removal mechanism). For example, FIG.15 shows a leveling mechanism 1503 that reduced the height level from aheight of 1517 to a smaller height of 1516. The leveling can take placeas the powder is dispensed by the powder dispenser, or after the powderis dispensed by the powder dispenser. The leveling can be synchronizedwith the powder dispensing mechanism. The leveling operation can beseparate from the powder dispensing operation. The leveling operationcan be integrated with the powder dispensing operation. The levelingmechanism may be heated or cooled. At least some of the components ofthe leveling mechanism may be heated or cooled. The leveling mechanismmay comprise openings though which gas may travel though. The gas may beany gas disclosed herein. The gas may aid in fluidizing the powdermaterial. In some embodiments, the leveling member (e.g., levelingmechanism) enables the powder to be substantially evenly distributedacross a powder bed. The leveling member may be exchangeable, removable,non-removable or non-exchangeable. The leveling member may compriseexchangeable parts. The leveling member may distribute powder across thepowder bed. The leveling member may be a part of the powder dispensingmechanism (e.g., powder dispenser). The rake (e.g., FIG. 11, 1103) is anexample of a leveling member. The leveling member can provide powderuniformity across the bed such that portions of the bed that areseparated from one another by at least about 1 mm, 2 mm, 3 mm, 4 mm, 5mm, or 10 mm, have a height deviation of at most about 10 mm, 9 mm, 8mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 500 μm, 400 μm, 300 μm,200 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm,or 10 μm; or of any value between the afore mentioned height deviationvalues. For example, the leveling member can provide powder uniformityacross the bed such that portions of the bed that are separated from oneanother by a distance of from about 1 mm to about 10 mm, have a heightdeviation from about 10 mm to about 10 μm. The leveling member mayachieve a deviation from a planar uniformity in at least one plane(e.g., horizontal plane) of at most about 20%, 10%, 5%, 2%, 1% or 0.5%,as compared to the average plane (e.g., horizontal plane) created by thetop of the powder bed.

FIG. 12A-F schematically depict vertical side cross sections of variousmechanisms for spreading and/or leveling the powder material. FIG. 12Aschematically depicts a knife 1207 situated substantially perpendicularto the surface 1203 moving in the direction 1205. FIG. 12B schematicallydepicts a knife 1207 situated substantially parallel to the surface 1208moving in the direction 1210. FIG. 12C schematically depicts a knife1212 situated substantially parallel to the surface 1213 moving in thedirection 1215. FIG. 12D schematically depicts a sprinkler 1217 situatedmoving in the direction 1220. FIG. 12E schematically depicts a roller1222 situated substantially parallel to the surface 1223 moving in thedirection 1225. FIG. 12F schematically depicts a roller 1227 situatedsubstantially parallel to the surface 1228 moving in the direction 1230.

FIGS. 14A-D schematically depict vertical side cross sections of variousmechanisms for spreading and leveling the powder material;parallelograms 1413, 1423, 1426, 1446, 1447, 1453, and 1456schematically depict a schematic representation of any blade describedherein; rectangles 1415, 1424, 1444 and 1454 schematically depict aschematic representation of any powder dispenser described herein.

FIG. 24 schematically depicts vertical side cross sections of amechanism for spreading, leveling, and removing the powder material. Inthis figure, parallelogram 2408 depicts a schematic representation ofany blade described herein, rectangle 2406 depict a schematicrepresentation of any powder dispenser described herein, and rectangle2404 depict a schematic representation of any powder removal memberdescribed herein.

In some examples, the leveling member comprises a roller (e.g., acylinder). The roller may comprise one or more opening ports (i.e.,powder exit ports) thorough which powder material can exit the roller.The exits may be located along the rectangular cross section of theroller (e.g., cylindrical roller). The rectangular cross section of theroller may comprise the height of the roller. The powder exit ports maybe situated randomly or in a pattern along the rectangular cross sectionof the roller. The powder exit ports may be situated along a line withinthe rectangular cross section of the roller. The roller may comprise atleast one opening port from which the powder enters the roller (i.e.,the powder entrance port). The powder entrance may be situated at thecircular surface area of the roller (e.g., the side of the roller), atits rectangular surface area, or at both circular of rectangularsurfaces. An opening (e.g., port) may be in the form comprising anellipse (e.g., a circle), parallelogram (e.g., rectangle or a square),triangle, any other geometric shape, an irregular shape, or any partialshape or combination of shapes thereof. The roller may comprise aninternal cavity that connects the powder at least one entrance port andthe one or more powder exit ports. The internal cavity may allow thepowder to flow from the entrance port to the exit port, thus forming afluid connection between the one or more entrance and exit ports. Thepowder material may travel (e.g., flow) though the internal cavity fromthe powder entrance to the powder exit. The shape and/or size of thepowder opening port may determine the amount of powder distributed fromthe roller. The roller may be rotatable. The roller may rotate along itsheight (e.g., along its long axis). The long axis of the roller may spanthe entire powder bed, or a part of the powder bed. The rate of rotationof the roller (revolutions of the roller) may determine the amount ofpowder distributed by the roller. The rate of rotation may determine thearea of powder distributed by the roller. The roller may be coupled to acontrol system. The control system may control the rate of rotations ofthe cylinder and/or the rate of its lateral (e.g., along a powder bed),horizontal or angular movement.

The roller may comprise a smooth surface, a rough surface, anindentation, a depression, or a cavity. The roller may be any of therollers disclosed herein. FIGS. 22, 2203, 2204 and 2205 shows examplesof various alternative rollers described herein. The roller of theleveling mechanism may at times rotate in the direction of lateralmovement of the leveling mechanism, or in a direction opposite of thedirection of lateral movement of the leveling mechanism. FIG. 22, 2201shows examples of the lateral movement direction of roller 2203. In thisexample, roller 2203 rotates opposite to the direction of movement ofthe leveling mechanism, along an axis that is both the long axis of theroller and normal to the lateral direction of the movement of the roller(2201). When the roller revolves (rotates), it may induce movement ofany atmosphere surrounding the roller. FIG. 22, 2207 shows examples ofthe movement of atmosphere surrounding the roller. The roller may besituated at a first distance above the surface of the layer of powdermaterial. The diameter of the roller may be at least 1*, 5*, 10*, 50*,100*, 500*, or more times (i.e., “*”) the first distance. The firstdistance may be at least about 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, or 600 μm. The firstdistance may be at most about 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, or 600 μm. The firstdistance may be any value between the afore-mentioned first distancevalues. For example, the first distance may be from about 10 μm to about400 μm, from about 300 μm to about 600 μm, or from about 250 μm to about450 μm. In some instances, the movement of the atmosphere surroundingthe roller may induce movement of the powder in the direction ofmovement. In some instances, the powder may be suspended within themoving portion of the atmosphere. The velocity of movement of theatmosphere may be highest within the narrowest distance between theroller and the surface of the powder material. The atmosphere around theroller may comprise circular movement of atmosphere portions. Theatmosphere around the roller may comprise laminar movement of atmosphereportions. In some instances, when the roller rolls in the direction(e.g., clockwise) of its lateral movement, powder may be pusheddownwards into the powder bed (e.g., FIG. 22, 2210 depicting the powderbed). In some instances, when the roller rolls in the direction opposite(e.g., counter clockwise) to the direction of its lateral movement,powder may be directed upwards (e.g., FIG. 22, depicting solid arrows2206 designating the direction of powder movement). The rotating rollermay generate a motion opposite (e.g., counter clockwise) to the lateraltranslational movement of the roller across the powder bed. The oppositemotion may comprise moving the powder forward (relative to the lateralmotion of the roller). The opposite motion may comprise moving thepowder upwards (e.g., above the top surface of the powder layer). Theopposite motion may comprise moving the powder both forward (relative tothe lateral motion of the roller) and upwards (e.g., above the surfaceof the powder layer). The upward and forward moving powder may form aboundary layer above the top leveled surface of the powder bed. Therotation of the roller may proceed to form the boundary layer until apredetermined height of powder is achieved. The roller may comprise apowder trapping compartment to trap any powder material that travels tothe direction behind the roller (relative to its lateral motion). Thepowder trapping compartment may be in the form of a curved surface(e.g., a cup or a spoon). In some examples, when the powder is thrownupwards, a powder removal mechanism (e.g., powder suction device) maycollect the excess of powder from the surface. FIG. 23, 2301 shows anexample of a powder removal mechanism. The leveling mechanism may spanthe entire width of the powder bed, entire length of the powder bed, ora portion of the powder bed. The leveling mechanism may comprise anarray of leveling members. The array of leveling members may be spacedapart evenly or unevenly. The array of leveling members may be spacedapart at most about 0.1 mm, 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4mm, or 5 mm. The array of leveling members may be spaced apart at leastabout 0.1 mm, 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm.The array of leveling members may be spaced apart between any of theafore-mentioned spaces of the leveling members. For example, array ofleveling members may be spaced apart from about 0.1 mm to about 5 mm,from about 1.5 mm to about 5 mm, or from about 0.1 mm to about 2 mm.

A controller may be operatively coupled to the leveling member andcontrol (e.g., direct and/or regulate) the leveling member. Thecontroller may control the rate of lateral movement of the roller. Thecontroller may control the revolution rate of the roller. The controllermay control the direction of the rotation of the roller. The controllermay control the amount indentations or depressions on the surface of theroller. The controller may control the degree of indentations ordepressions on the surface of the roller. The controller may control thetemperature of the roller. The controller may control the roughness ofthe surface of the roller. The controller may control the roughness ofthe powder surface created by the roller.

In some examples, the leveling mechanism (e.g., leveling member)prevents the accumulation of powder in the direction of movement of theleveling member (e.g., a lateral movement). In some instances, theleveling mechanism comprises a blade. The blade may be of any bladeshape disclosed herein. The blade may comprise a concave or convexplane. The blade may be able to level the powder material and cut,remove, shear or scoop the unwanted powder material. The blade may havea shape of a scoop, or shovel. The blade may have a shape of the letter“L” (e.g., FIG. 15, 1515 depicting an alternative blade). The blade mayhave an indentation, depression, or cavity. The indentation can be ofany shape. For example, the indentation can comprise a shape having anelliptical (e.g., circular), rectangular (e.g., square), triangular,pentagonal, hexagonal, octagonal, any other geometric shape, or a randomshape. The blade may have an indentation that is able to cut, push, liftand/or scoop the powder material as it moves (e.g., laterally). FIG. 15shows an example of a blade 1503 having an indentation 1514 in whichpowder is scooped as the blade moves laterally in the direction 1504. Insome instances, the blade can scoop at least about 0.1 cm³, 0.15 cm³,0.2 cm³, 0.25 cm³, 0.3 cm³, 0.35 cm³, 0.4 cm³, 0.45 cm³, 0.5 cm³, or0.55 cm³ of powder material. The blade can scoop at most about 0.1 cm³,0.15 cm³, 0.2 cm³, 0.25 cm³, 0.3 cm³, 0.35 cm³, 0.4 cm³, 0.45 cm³, 0.5cm³, 0.55 cm³, 0.6 cm³, 0.65 cm³, 0.7 cm³, 0.8 cm³, or 0.9 cm³ of powdermaterial. The blade can scoop powder material between any of theafore-mentioned quantities of powder material. For example, the bladecan scoop powder material in a volume from about 0.1 cm³ to about 0.55cm³, from about 0.1 cm³ to about 0.3 cm³, or from about 0.25 cm³ toabout 0.55 cm³.

The blade may comprise at least one slanted plane. For example, the partcloser to the tip of the blade may comprise at least one slanted plane(e.g., in FIG. 20, the blade part closer to the tip of blade 1503, is2005). The blade may comprise a first slanted plane, which may form anangle delta (δ) with average plane formed by the top surface of thelayer of powder material, the substrate or the base (e.g., FIG. 20,2001). The blade may comprise a second slanted plane, which may form anangle zeta (ζ) with average plane formed by the top surface of the layerof powder material, with the substrate or with the base (e.g., 2003).The first and second slanted planes may be curved or planar. The firstand second plane may for a symmetric blade with the axis of symmetry inthe center between the two planes. The first and second plane may forman asymmetric blade in relation to the axis of symmetry in the centerbetween the two planes. The blade may comprise at least one planeperpendicular to the average plane formed by the top surface of thelayer of powered material. In the direction of movement, the angle deltamay be an acute positive angle or an obtuse positive angle (i.e., incounter-clockwise direction). The angles delta and zeta may be equal.The angles gamma and zeta may be different. Gamma may be larger thanzeta. Zeta may be larger than delta. Viewed from the same direction, theangles delta, zeta or both may be obtuse angles. Viewed from the samedirection, the angles gamma, zeta or both may be acute angles. Viewedfrom the same direction, the angles gamma, zeta or both may be rightsangles. The first and second planes may be parallel to each other. Thefirst and second planes may be non-parallel to each other. Zeta and/ordelta may be at least about 1°, 5°, 10°, 15°, 20°, 30°, 40°, 50°, 60°,70°, 80°, 90°, 100°, 120°, 125°, 130°, 135°, 140°, 145°, 150°, 155°,160°, 165°, 170°, 175° (degrees) or more. Delta and/or zeta may be atmost about 5°, 10°, 15°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°,120°, 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160°, 165°, 170°, 175°or less. Delta and/or zeta may be of any value between theafore-mentioned degree values for delta and/or zeta. For example, deltaand/or zeta may be of a value from about 1° to about 175°, from about 1°to about 90°, from about 90° to about 175°, or from about 15° to about135°.

The blade may comprise a tapered bottom plane (e.g., a chamfer). Thetapered bottom plane may be planar or curved. The blade may comprise aplanar or a curved plane. The radius of curvature may be above thetapered bottom plane (e.g., away from the direction of the substrate),or below the tapered bottom plane (e.g., towards the direction of thesubstrate). For example, FIG. 20 shows a bottom of a blade 2001 that istapered in the direction of movement 2002, and is planar. The taperedbottom plane (e.g., a planar plane) may form an angle epsilon (ε) withthe average top surface of the powder material, with the substrate orwith the base, or with a plane parallel thereto. The angle may be apositive acute angle or a positive obtuse angle. The blade angle (delta“δ”) may form a positive obtuse angle, and the tapered bottom angle(epsilon) may form a positive acute angle when viewed from the sameviewing position. The blade angle (delta) may form a positive obtuseangle, and the tapered bottom angle (epsilon) may form a positive acuteangle. The blade angle (delta) may form a positive acute angle, and thetapered bottom angle (epsilon) may form a positive obtuse angle. Theblade may be substantially perpendicular to the average surface of thelayer of powder material, the substrate, or the base. For example, FIG.20 shows a blade forming an obtuse positive angle delta (δ), having atapered bottom, which forms a positive acute angle epsilon (ε). In someinstances, both the blade angle delta and the tapered bottom angleepsilon may form positive obtuse angles. In some instances, both theblade angle delta and the tapered bottom angle epsilon may form positiveobtuse acute. Epsilon and delta may have a different value. Positiveangles may be counter-clockwise angles. Positive may be designated as afirst direction. Both positive angles may be positive when viewed fromthe same viewing position. Epsilon may be at least about 0.1°, 0.2°,0.3°, 0.4°, 0.5°, 0.6°, 0.7°, 0.8°, 0.9°, 1°, 2°, 3°, 4°, 5°, 6°, 7°,8°, 9°, 10°, 15°, 20°, 30°, 40°, or 50°. Epsilon may be at most about0.1°, 0.2°, 0.3°, 0.4°, 0.5°, 0.6°, 0.7°, 0.8°, 0.9°, 1°, 2°, 3°, 4°,5°, 6°, 7°, 8°, 9°, 10°, 15°, 20°, 30°, 40°, or 50°. Epsilon may be ofany value between the aforementioned degree values for epsilon. Forexample, epsilon may be of a value from about 0.1° to about 50°, fromabout 0.1° to about 20°, from about 20° to about 50°, or from about 10°to about 30°.

In some instances, the tapered bottom is of a smaller height as comparedto the height of the entire blade. An example of the relative heights isshown in FIG. 20, depicting “h” as the height of the tapered end. Insome instances, “h” is at least about 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm,0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm,1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2.0 mm. Insome instances, “h” is at most 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm,0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm,1.5 mm, 1.6 mm, 1.7 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2.0 mm. In someinstances, “h” is any value between the afore-mentioned heights “h.” Forexample, “h” may be from about 0.1 mm to about 2.0 mm, from about 0.1 mmto about 1.0 mm, from about 0.9 mm to about 2.0 mm, or from about 0.7 mmto about 1.5 mm.

At least part of the blade may comprise elemental metal, metal alloy, anallotrope of elemental carbon, ceramic, plastic, rubber, resin, polymer,glass, stone, or a zeolite. At least part of the blade may comprise ahard material. At least part of the blade may comprise a soft material.The at least part of the blade may comprise the tip of the blade; thebottom of the blade facing the bottom of the container, the substrate orthe base. At least part of the blade may comprise a material that is nonbendable during the leveling of the powder material. At least part ofthe blade may comprise a material that is substantially non-bendablewhen pushed against the powder material during the leveling process. Atleast part of the blade may comprise a material that is bendable whenpushed against object comprising a transformed powder material that wasallowed to harden. At least part of the blade may comprise a materialthat is substantially non-bendable during the leveling of the powdermaterial, or during removal of an object comprising a transformed powdermaterial that was allowed to harden. At least part of the blade maycomprise an organic material. At least part of the blade may compriseplastic, rubber or Teflon®. The blade may comprise a material to whichthe powder material does not cling. At least part of the blade maycomprise a coating to which the powder material does not cling. At leastpart of the blade may be charged to prevent clinging of the powdermaterial.

The blade may comprise compliant mounting. The blade may be able topivot or swivel relative to the compliant mounting. The blade may besuspended on springs. The spring may be attached to the compliantmounting. The blade may be permanently fastened (e.g., to the compliantmounting). In some embodiments, the blade may be prevented frompivoting. In some embodiments, the blade may be prevented fromswiveling. The blade may be exchangeable, removable, non-removable, ornon-exchangeable. FIG. 14A schematically shows a blade 1413 (whichrepresents any blade described herein) on a mounting 1412 (e.g., acompliant mounting) that is able to translate horizontally 1411. Themounting may allow the blade to move vertically, horizontally, or at anangle. FIG. 14B schematically shows two blades 1423 and 1426respectively on mountings 1422 and 1425 with arrows therein representingvertical movements. The mounting may comprise one or more springs. Themounting may allow the blade to move vertically when confronting anobstacle. The obstacle may be a hardened material as described herein.The obstacle may be a generated part of a 3D object, or a generated 3Dobject, or a hardened material that did not form part of the 3D object.The blade may be deformed when confronting the object. The blade may besubstantially non-deformed when confronting the object. The concaveplane may be utilized in leveling the layer of powder material that isdeposited in the enclosure (e.g., above the substrate or above thebase). The powder material may be pushed by the blade (e.g., by theconcave plane). The powder material may be pushed by the blade in thedirection of its movement. The powder material may be pushed (e.g.,relocated, sheared, or removed) by the blade in the direction oppositeto its movement. The powder material may be pushed by the blade in thedirection other than a direction of its movement. The powder materialmay be pushed by the blade in the direction other than a direction ofits movement or opposite to its movement. In some examples, the concaveplane may not face the bottom of the enclosure, of the substrate or ofthe base.

The blade may be movable. For example, the blade may be movablehorizontally, vertically or at an angle. The blade may be movablemanually or automatically (e.g., by a mechanism controlled by acontroller). The movement of the blade may be programmable. The movementof the blade may be predetermined. The movement of the blade may beaccording to an algorithm.

The layer dispensing mechanism may comprise a leveling mechanism. Thelayer dispensing mechanism may comprise a powder dispensing mechanismand a leveling mechanism. The layer dispensing mechanism may be movable.The layer dispensing mechanism may be movable horizontally, verticallyor at an angle. The layer dispensing mechanism may be movable manuallyor automatically (e.g., controlled by a controller). The movement of thelayer dispensing mechanism may be programmable. The movement of thelayer dispensing mechanism may be predetermined. The movement of thelayer dispensing mechanism may be according to an algorithm.

The powder dispensing mechanism (e.g., powder dispenser) may be movable.The powder dispensing mechanism may be movable horizontally, verticallyor at an angle. The powder dispensing mechanism may be movable manuallyor automatically (e.g., controlled by a controller).

The powder removal mechanism may be movable. The removal mechanism maybe movable horizontally, vertically or at an angle. The removalmechanism may be movable manually or automatically (e.g., controlled bya controller). The movement of the powder removal mechanism may beprogrammable. The movement of the powder removal mechanism may bepredetermined. The movement of the powder removal mechanism may beaccording to an algorithm.

The powder leveling mechanism may be movable. The leveling mechanism maybe movable horizontally, vertically or at an angle. The levelingmechanism may be movable manually or automatically (e.g., controlled bya controller). The movement of the leveling mechanism may beprogrammable. The movement of the leveling mechanism may bepredetermined. The movement of the leveling mechanism may be accordingto an algorithm.

The layer dispensing mechanism may be able to travel in a horizontaldirection from one side of the enclosure to its other side. The powderdispensing mechanism, powder removal mechanism, leveling mechanismand/or blade may be able to travel in a horizontal direction from oneside of the enclosure to its other side. The vertical position of thepowder dispensing mechanism, powder removal mechanism, levelingmechanism and/or blade may be adjustable. The horizontal position of thepowder dispensing mechanism, powder removal mechanism, levelingmechanism and/or blade may be adjustable. The angular position of thepowder dispensing mechanism, powder leveling mechanism, levelingmechanism and/or blade may be adjustable.

In some examples, the layer dispensing mechanism comprises at least onepowder dispensing mechanism and at least one leveling member. The atleast one powder dispensing mechanism and at least one leveling membermay be connected or disconnected. FIG. 14A schematically shows a blade1413 (which represents any blade described herein) connected via aconnector 1437 to a powder dispensing mechanism 1415 (which representsany powder dispensing mechanism described herein). The at least onepowder dispensing mechanism and at least one leveling member may travelat different speeds or at the same speed. The at least one powderdispensing mechanism and at least one leveling member may besimultaneously controlled by the controller, or non-simultaneouslycontrolled (e.g., sequentially controlled) by the controller. The speedand/or position of the at least one powder dispensing mechanism and theat least one leveling member may be simultaneously controlled by thecontroller, or non-simultaneously controlled (e.g., sequentiallycontrolled) by the controller. The speed and/or position of the at leastone powder dispenser and at least one leveling member may be dependentor independent on each other. Relative to the direction of travel, theleveling member may follow the powder dispensing mechanism. Relative tothe direction of travel, the leveling member may precede the powderdispensing mechanism. In some embodiments, at least one powder dispensermay be disposed between two leveling members. FIG. 14B schematicallyshow an example of a first leveling member having a blade 1423, a secondleveling member having a blade 1426, and a powder dispenser 1424. Thetwo leveling members may be vertically translatable (e.g., FIG. 14B) ornon-translatable (e.g., FIG. 14D). In some examples, the bottom face ofboth leveling members (which faces the exposed surface of the powderbed) is positioned at the same vertical height relative to the bottom ofthe enclosure, substrate or base (e.g., FIG. 14D). In some examples, thebottom face of both leveling members, which faces the powder bed, arepositioned at the different vertical height relative to the bottom ofthe enclosure, substrate or base (e.g., FIG. 14B). For example, relativeto the direction of movement, the bottom face of the frontal levelingmember (e.g., FIG. 14B, 1426) may be higher than the bottom face of thedistal leveling member (e.g., 1423) when moving in a first direction(e.g., 1430). When the layer dispensing mechanism reaches the end of thepowder bed, or precedes the end of the powder bed, the direction ofmovement may switch and thus the level of the bottom face of theleveling members may switch accordingly.

In some examples, at least one powder dispensing member (e.g., powderdispenser, FIG. 14A, 1415) may precede at least one leveling member(e.g., 1412 and 1413 collectively) relative to the direction of movement(e.g., 1411). In this example, powder dispensed from the powderdispenser may be leveled as the leveling system follows the powderdispenser. When the layer dispensing mechanism reaches the end of thepowder bed, or precedes the end of the powder bed, the direction ofmovement may switch and thus the leveling member may move to a positionthat allows the powder dispensing member to precede the leveling member.FIG. 14C shows an example of switching the position of the levelingmember (from 1443 and 1446 to 1445 and 1447 respectively), relative tothe powder dispenser 1444, while switching the direction of movementfrom 1451 to 1452. Such movement may be, for example, a 180-degreerotation about the axis that is substantially perpendicular to theaverage top surface of the layer of powder bed, to the substrate, or tothe base. The axis of rotation may go through the powder dispensingmechanism (e.g., 1441). The axis of rotation may go through the chute(e.g., cascade or drop) of powder material from the powder dispensingmechanism. In some examples, the powder is dispensed when the layerdispensing mechanism (e.g., comprising the leveling member and thepowder dispenser) moves in a first direction, and the deposited layer ofpowder material is leveled when the layer dispensing mechanism moves inthe opposite direction. The powder material may be dispensed by thelayer dispensing mechanism (e.g., the powder dispenser) when the layerdispensing mechanism travels in a first direction. The powder materialmay be leveled by the leveling mechanism when the layer dispensingmechanism travels in a second direction. The first and second directionmay be the same direction. The first and second direction may beopposite directions.

In some cases, the mechanism that is configured to deliver a powderedmaterial (e.g., the powder dispenser) to the powder bed can be anultrasonic powder dispensing mechanism. The mechanism that is configuredto deliver the powder to the powder bed can be a vibratory powderdispensing mechanism. The powder dispenser may comprise a vibrator or ashaker. The mechanism configured to deliver the powder from to thesubstrate can comprise a vibrating mesh. The vibration may be formed byan ultrasonic transducer, a piezo-electric device, a rotating motor(e.g., having an eccentric cam), or any combination thereof. Theultrasonic and/or vibratory powder dispensing mechanism can dispensepowder in one, two, or three dimensions. The frequency of an ultrasonicand/or vibratory disturbance of the dispenser can be chosen such thatpowder is delivered to the powder bed at a predetermined rate. Theultrasonic and/or vibratory dispenser can dispense powder onto thepowder bed from a location above the powder bed. The ultrasonic and/orvibratory dispenser can dispense powder onto the powder bed from alocation that is at a relatively higher height relative to the powderbed (e.g., the top of the enclosure). The ultrasonic and/or vibratorydispenser can dispense powder onto the powder bed in a downward orsideward direction. The ultrasonic and/or vibratory dispenser candispense powder onto the powder bed in a downward direction. The powdermay be dispensed using gravitational force. The ultrasonic and/orvibratory dispenser can be a top-dispenser that dispenses the powderfrom a position above the substrate, the base or the powder bed (or acontainer for accommodating the powder bed). The vibrator may comprise aspring. The vibrator may be an electric or hydraulic vibrator.

The powder dispenser can comprise a vibrator. FIG. 15, 1507 shows anexample for a powder dispenser 1509 with a vibrator 1507. The powderdispenser can comprise two or more vibrators (e.g., an array ofvibrators). The array of vibrators can be arranged linearly,non-linearly, or at random. The array of vibrators can be arranged alongthe opening of the powder dispenser, or in proximity thereto. The powderdispenser can comprise multiple opening ports. The array of vibratorscan be situated along the array of opening ports (e.g., the multipleopenings). The vibrators can be arranged along a line. The vibrators canbe arranged along a linear pattern. The vibrators can be arranged alonga non-linear pattern. The arrangement of the vibrators can determine therate at which the powder exits the powder dispenser. The vibrator(s) mayreside on a face of the powder dispenser. FIG. 16A shows an example of apowder dispenser 1605 comprising a mesh 1607 and a vibrator 1603. Thevibrator may reside next to the exit opening (e.g., port). The powderdispenser can comprise a mesh that is connected to a vibrator. Thepowder dispenser comprises a mesh that is capable of vibrating. Thevibrator(s) can vibrate at least part of the powder material within thepowder dispenser (e.g., FIG. 16A, 1604). The vibrators(s) can vibrate atleast a part of the powder dispenser body. The body of the powderdispenser (e.g., the powder reservoir) may comprise a light materialsuch as a light elemental metal or metal alloy (e.g., aluminum). Thevibrators can be controlled manually or automatically (e.g., by acontroller). The vibrator frequency may be at least about 20 Hertz (Hz),30 Hz, 40 Hz, 50 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, 100 Hz, 110 Hz, 120 Hz,130 Hz, 140 Hz, 150 Hz, 160 Hz, 170 Hz, 180 Hz, 190 Hz, 200 Hz, 210 Hz,220 Hz, 230 Hz, 240 Hz, 250 Hz, 260 Hz, 270 Hz, 280 Hz, 290 Hz, 300 Hz,350 Hz, 400 Hz, 450 Hz, 500 Hz, 550 Hz, 600 Hz, 700 Hz, 800 Hz, 900 Hz,or 1000 Hz. The vibrator frequency may be at most about 20 Hertz (Hz),30 Hz, 40 Hz, 50 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, 100 Hz, 110 Hz, 120 Hz,130 Hz, 140 Hz, 150 Hz, 160 Hz, 170 Hz, 180 Hz, 190 Hz, 200 Hz, 210 Hz,220 Hz, 230 Hz, 240 Hz, 250 Hz, 260 Hz, 270 Hz, 280 Hz, 290 Hz, 300 Hz,350 Hz, 400 Hz, 450 Hz, 500 Hz, 550 Hz, 600 Hz, 700 Hz, 800 Hz, 900 Hz,or 1000 Hz. The vibrator frequency may be any number between theafore-mentioned vibrator frequencies. For example, the vibratorfrequency may be from about 20 Hz to about 1000 Hz, from about 20 Hz, toabout 400 Hz, from about 300 Hz to about 700 Hz, or from about 600 Hz toabout 1000 Hz. The vibrators in the array of vibrators can vibrate inthe same or in different frequencies. The vibrators can have a vibrationamplitude of at least about 1 times the gravitational force (G), 2 timesG, 3 times G, 4 times G, 5 times G, 6 times G, 7 times G, 8 times G, 9times G, 10 times G, 11 times G, 15 times G, 17 times G, 19 times G, 20times G, 30 times G, 40 times G, or 50 times G. The vibrators can have avibration amplitude of at most about 1 times the gravitational force(G), 2 times G, 3 times G, 4 times G, 5 times G, 6 times G, 7 times G, 8times G, 9 times G, 10 times G, 11 times G, 15 times G, 17 times G, 19times G, 20 times G, 30 times G, 40 times G, or 50 times G. Thevibrators can vibrate at an amplitude having any value between theafore-mentioned vibration amplitude values. For example, the vibratorscan vibrate at an amplitude from about 1 times G to about 50 times G,from about 1 times G to about 30 times G, from about 19 times G to about50 times G, or from about 7 times G to about 11 times G.

In some cases, the mechanism configured to deliver the powder from thereservoir to the substrate (i.e., powder dispenser) can be a screw, anelevator, or a conveyor. In some cases, the mechanism configured todeliver the powder from the reservoir to the substrate (i.e., powderdispenser) can be a screw. The screw can be a rotary screw in a vessel.When the screw is rotated powder can be dispensed from the screw thoughan exit opening (e.g., port). The screw can dispense powder in anupward, lateral or downward direction relative to the substrate. Thespacing and size of the auger screw threads can be chosen such that apredetermined amount of powder is dispensed on to the substrate witheach turn or partial turn of the screw in the screw. The turn rate ofthe screw in the auger can be chosen such that powder is dispensed onthe substrate at a predetermined rate. In some cases, powder dispensedby the screw can be spread on at least a fraction of the substrate 904by a rotary screw, linear motion of a spreading tool, and/or one or morebaffles. The screw can be an Archimedes screw. The screw can be an augerscrew.

The powder dispenser may be shaped as an inverted cone, a funnel, aninverted pyramid, a cylinder, any irregular shape, or any combinationthereof. Examples of funnel dispensers are depicted in FIGS. 13A-D,showing side cross sections of a powder dispenser. The bottom opening ofthe powder dispenser (e.g., FIG. 13A, 1334) may be completely blocked bya vertically movable plane (e.g., 1305) above which powder is disposed(e.g., 1304). The plane can be situated directly at the opening, or at avertical distance “d” from the opening. The movement (e.g., 1302) of thevertically movable plane may be controlled. When the plane is movedvertically upwards (e.g., away from the base (e.g., 1310)), sideopenings are formed between the plane and the edges of the powderdispenser, out of which powder can slide though the funnel opening(e.g., 1307). The powder dispenser may comprise at least one mesh thatallows homogenous (e.g., even) distribution of the powder on to thepowder bed (or container accommodating the powder bed). The mesh can besituated at the bottom opening of the powder dispenser (e.g., 1334) orat any position between the bottom opening and the position at which theplane completely blocks the powder dispenser (e.g., at any positionwithin the distance “d” in FIG. 13A).

The powder dispenser can be a double mesh dispenser (e.g., FIG. 13C).The double mesh dispenser may be shaped as an inverted cone, a funnel,an inverted pyramid, a cylinder, any irregular shape, or any combinationthereof. Examples of funnel dispensers are depicted in FIG. 13A-D,showing cross sections of a powder dispenser. The bottom of the doublemesh dispenser can comprise an opening (e.g., 1335). The opening maycomprise two meshes (e.g., 1323) of which at least one is movable (e.g.,horizontally). The two meshes are aligned such that the opening of onemesh can be completely blocked by the second mesh. A horizontal movement(e.g., 1320) of the at least one movable mesh may misalign the twomeshes and form openings that allow flow of powder from the reservoirabove the two meshes (e.g., 1319) down towards the direction of thepowder bed (e.g., 1324). The misalignment of the meshes can alter thesize and/or shape of the openings though which the powder material canexit the powder dispenser. The openings can have a fundamental lengthscale of at least about 0.001 mm, 0.01 mm, 0.03 mm, 0.05 mm, 0.07 mm,0.09 mm, 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 10 mm. The openingscan have a fundamental length scale of at most about 0.001 mm, 0.01 mm,0.03 mm, 0.05 mm, 0.07 mm, 0.09 mm, 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5mm, or 10 mm. The openings can have a fundamental length scale betweenany of the aforementioned values. For example, the openings can have afundamental length scale from about 0.001 mm to about 10 mm, or from 0.1mm to about 5 mm.

The powder dispenser may comprise an exit opening port that resideswithin a face of the powder dispenser. The face may be the bottom of thepowder dispenser, which faces the substrate, the base, or the bottom ofthe enclosure (e.g., chamber). FIG. 13C shows an example of a powderdispenser 1318 having a bottom facing exit opening port 1335. The facein which the exit opening port resides may be different than the bottomface of the power dispenser. For example, the face may be a side of thepowder dispenser. The face may be a face that is not parallel to thelayer of powder material. The face may be substantially perpendicular tothe average plane formed by the top surface of the powder bed. FIG. 15shows an example of a powder dispenser 1509 having a side exit openingport 1511 that is substantially perpendicular to the top surface of thepowder bed 1506. The face may be substantially perpendicular to theaverage plane of the substrate or of the base. The face may be situatedat the top face of the powder dispenser. The top face of the dispensermay be the face that faces away from the substrate, base or bottom ofthe enclosure. The top face of the dispenser may be the face that facesaway from the exposed surface of the powder bed. The face may be a sideface. The side face may be a face that is not the bottom or the topface. A plane in the face (e.g., the entire face) may lean towards thepowder bed, the substrate, the bottom of the container, or the base.Leaning may comprise a plane that is curved towards the substrate, thebase, and the bottom of the enclosure or towards the powder bed. Thecurved plane may have a radius of curvature centering at a point belowthe bottom of the powder dispenser. The curved plane may have a radiusof curvature centering at a point above the bottom of the powderdispenser. Leaning may comprise a plane forming an acute angle with anaverage surface of the substrate, the base or a top surface of the layerof powder material, or with a plane parallel thereto. For example, aplane at the bottom face of the powder dispenser may from an acute or anobtuse angle (phi, φ) with the average plane formed by the top surfaceof the powder material, by the substrate or by the base. FIGS. 18B and18D each shows an example of a powder dispenser (1813 and 1833respectively), having a side exit opening port (1812 and 1831respectively), that forms an angle phi (φ) with the top surface of thepowder material 1810 and 1830 respectively (or with a line parallelthereto). FIG. 18B shows an example of an acute angle phi, and FIG. 18Bshows an example of an obtuse angle phi. The angle phi may be at leastabout 5°, 10°, 15°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°,120°, 130°, 140°, 150°, 160°, or 170°. Phi may be at most about 5°, 10°,15°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, or 170°. The angle phi may be of any value between theafore-mentioned degree values for phi. For example, the angle phi may befrom about 5° to about 170°, from about 5° to about 90°, or from about90° to about 170°.

The powder dispenser may comprise a bottom having a first slanted bottomplane. In some instances, one edge (side) of the plane at the bottom ofthe powder dispenser lies vertically above another edge of that plane.The plane may be convex or concave. The angle of the first slantedbottom plane may be adjustable or non-adjustable. The first slantedbottom plane may face the bottom of the enclosure, the substrate or thebase. The bottom of the powder dispenser may be a slanted plane. FIG. 17shows an example of a powder dispenser 1702 with a slanted bottom plane1711. The first slanted bottom plane may form a first acute angle (gamma“γ”) in a first direction (e.g., positive direction) with a planeparallel to the average top surface of the powder material, thesubstrate or the base. The bottom of the powder dispenser may compriseone or more additional planes. The one or more additional planes may beadjacent to the bottom of the powder dispenser. The one or moreadditional planes may be connected to the bottom of the powderdispenser. The one or more additional planes may be disconnected fromthe powder dispenser. The one or more additional planes may beextensions of the bottom face of the powder dispenser. The one or moreadditional planes may be slanted. The angle of the one or moreadditional planes may be adjustable or non-adjustable. The one or moreadditional planes that are slanted may form an acute angle (theta “θ”)in a second direction with a plane parallel to the average top surfaceof the powder material. The direction (first and/or second) may beclockwise or anti-clockwise direction. The direction may be positive ornegative direction. The first direction may be the same as the seconddirection. The first direction may be opposite to the second direction.For example, the first and second direction may be clockwise. The firstand second direction may be anti-clockwise. The first direction may beclockwise and the second direction may be anti-clockwise. The firstdirection may be anti-clockwise and the second direction may beclockwise. The first and second direction may be viewed from the sameposition. At least part of the one or more additional planes may besituated at a vertical position that is different than the bottom of thefirst slanted bottom plane. At least part of the one or more additionalplanes may be situated at a vertical position that is higher than thebottom of the first slanted bottom plane. At least part of the one ormore additional planes may be situated at a vertical position that islower than the bottom of the first slanted bottom plane. The lower mostposition of the one or more additional planes may be situated at avertical position that is higher or lower than the lower most positionof the first slanted bottom plane. The upper most position of the one ormore additional planes may be situated at a vertical position that ishigher or lower than the upper most position of the first slanted bottomplane. The one or more additional plane may comprise a conveyor. Theconveyor can move in the direction of movement of the powder dispenser,or in a direction opposite to the direction of movement of the powderdispenser. FIG. 16D shows an example of a powder dispenser 1634 having aslanted bottom plane 1639, and an additional plane parallel to the base,which comprises a conveyor 1640, where the conveyor moves opposite tothe direction of movement 1638. Theta and/or delta may be at least about5°, 10°, 15°, 20°, 30°, 40°, 50°, 60°, 70°, or 80°. Theta and/or deltamay be at most about 5°, 10°, 15°, 20°, 30°, 40°, 50°, 60°, 70°, or 80°.Theta and/or delta may be of any value between the afore-mentioneddegree values for gamma and/or delta. For example theta and/or delta maybe from about 5° to about, 80°, from about 5° to about, 40°, or fromabout 40° to about, 80°.

The one or more additional plane may comprise a plane that ishorizontally separated from the powder exit opening (e.g., port) by agap. FIG. 28 shows an example of a powder dispenser 2839 having anadditional slanted plane 2733 that is separated from the opening 2835 bya gap. The gap may be adjustable. The angle of the slanted plane may beadjustable. The angle may be any of the aforementioned theta (θ) values.The top surface of the slanted plane may be flat or rough. The topsurface of the slanted plane may comprise extrusions or depressions. Thedepressions or extrusions may be random or follow a pattern. The topsurface of the slanted surface may be blasted (e.g., by any blastingmethod disclosed herein). The top surface of the slanted surface may beformed by sanding with a sand paper. The sand paper may be of at mostabout 24 grit, 30 grit, 36 grit, 40 grit, 50 grit, 60 grit, 70 grit, 80grit, 90 grit, 100 grit, 120 grit, 140 grit, 150 grit, 160 grit, 180grit, 200 grit, 220 grit, 240 grit, 300 grit, 360 grit, 400 grit, 600grit, 800 grit, or 1000 grit. The sand paper may be of at least 24 grit,30 grit, 36 grit, 40 grit, 50 grit, 60 grit, 70 grit, 80 grit, 90 grit,100 grit, 120 grit, 140 grit, 150 grit, 160 grit, 180 grit, 200 grit,220 grit, 240 grit, 300 grit, 360 grit, 400 grit, 600 grit, 800 grit, or1000 grit. The sand paper may be a sand paper between any of the aforementioned grit values. For example, the sand paper may be from about 60grit to about 400 grit, from about 20 grit to about 300 grit, from about100 grit to about 600 grit, or from about 20 grit to about 1000 grit.The roughness of the top surface of the slanted plane may be equivalentto the roughness of the sand paper mentioned herein. The roughness ofthe top surface of the slanted plane may be equivalent to a theroughness of a treatment with the sand paper mentioned herein. Theslanted plane (e.g., 2833) and the body of the powder dispenser (e.g.,the reservoir 2839) may be of the same type of material or of differenttypes of materials. The slanted plane may comprise a rougher materialthan the one substantially composing the body of the powder dispenser.The slanted plane may comprise a heavier material than the onesubstantially composing the body of the powder dispenser. The slantedplane may comprise a harder (e.g., less bendable) material than the onesubstantially composing the body of the powder dispenser. For example,the body of the powder dispenser may be made of a light metal (e.g.,aluminum), while the slanted plane may be made of steel or a steelalloy. The slanted plane may be mounted, while the body of the powderdispenser may vibrate or bend. The powder dispensed out of the exitopening (e.g., port) of the powder dispenser reservoir (e.g., FIG. 28,2839) may travel downwards using the gravitational force (e.g., 2834),contact the slanted plane (e.g., 2733) during its fall, bounce off theslanted plane, and continue its downward fall (e.g., 2832) to the powderbed (e.g., 2831), or to the substrate or base (e.g., 2830). In someembodiments, as the powder material exits the powder dispensingmechanism (e.g., member) to the environment of the enclosure (e.g.,chamber) and travels in the vertical direction of the powder bed (i.e.,travels down towards the powder bed), it encounters at least oneobstruction. The obstruction can be a surface. The surface can bestationary or moving (e.g., a conveyor). The surface can be rough orsmooth. The obstruction comprises a rough surface. The obstruction canbe a slanted surface that forms an angle with the exposed surface of thepowder bed. The angle can be any of the theta angles described herein.The powder removing mechanism (e.g., member) may be integrated withinthe powder dispensing member to form a powder dispensing-removing memberdescribed herein.

FIG. 18C shows an example of a powder dispenser 1824 with a slantedbottom plane 1821 that forms an anti-clockwise angle gamma with a planeparallel to the base 1820; the powder dispenser having an additionalplane 1823 that is connected to the powder dispenser 1824, is slantedand forms an anti-clockwise angle theta with a plane parallel to thebase, where theta is different (larger) than gamma; and the plane 1821both starts at a higher vertical position (d1) than the plane 1823 (d2),and ends at a higher vertical position (d2) than the ending position ofplane 1823 (d3) relative to the base.

The powder dispenser may comprise a bottom having a vertical crosssection forming a first curved bottom plane. The first curved bottomplane may have a radius of curvature that is situated below the bottomof the powder dispenser (e.g., in the direction of the substrate). Thefirst curved bottom plane may have a radius of curvature that issituated above the bottom of the powder dispenser (e.g., in thedirection away from the substrate). The radius of curvature of the firstcurved bottom plane may be adjustable or non-adjustable. FIG. 19A andFIG. 19C show examples of vertical cross sections of powder dispensers1901 and 1921 respectively having curved bottom planes 1902 and 1922respectively. The bottom of the powder dispenser may comprise one ormore additional planes. The one or more additional planes may beadjacent to the bottom of the powder dispenser. The one or moreadditional planes may be connected to the bottom of the powderdispenser. The one or more additional planes may be disconnected fromthe powder dispenser. The one or more additional planes may beextensions of the bottom face of the powder dispenser. The one or moreadditional planes may be curved. The radius of curvature of the one ormore additional planes may be adjustable or non-adjustable. The verticalcross section of the one or more additional curved planes may have aradius of curvature that is situated below the one or more additionalcurved planes (e.g., towards the direction of the substrate). Thevertical cross section of the one or more additional curved planes mayhave a radius of curvature that is situated above the one or moreadditional curved planes (e.g., towards the direction away from thesubstrate). The radius of curvature of the one or more additional curvedplanes may be the same or different than the radius of curvature of thefirst curved bottom plane. The radius of curvature of the one or moreadditional curved planes may be smaller or larger than the radius ofcurvature of the first curved bottom plane. FIG. 19A shows an examplesof a powder dispenser 1901 with curved bottom plane 1902 having a radiusof curvature r₁, and an additional curved plane 1905 that is connectedto the curved bottom plane 1902, and has a radius of curvature r₂,wherein r₂ is smaller than r₁, and both radii are situated below thebottom of the powder dispenser and the additional plane, towards thedirection of the substrate 1906. The one or more additional curvedplanes and the first curved bottom plane may be situated on the samecurve. FIG. 19D shows an examples of vertical cross section of a powderdispenser 1931 with curved bottom plane 1932 and having a radius ofcurvature r₁₂, that extends beyond the position of the powder dispenserexit opening port 1933, and thus forms an “additional curved plane”1935. In this example, the vertical cross section of the “additionalcurved plane” and the bottom of the powder dispenser are situated on thesame curve whose radius of curvature is situated below the bottom of thepowder dispenser, in the direction of the substrate 1936. The powderdispenser may have a planar bottom that may or may not be slanted. Thepowder dispenser may have a planar bottom that is parallel to thesubstrate (or to an average plane formed by the substrate). The powderdispenser may have one or more additional planes that are curved. Theradius of curvature of the curved planes (or a vertical cross sectionthereof) may be situated below the curved plane (e.g., in the directionof the substrate). FIG. 19B shows an example of vertical cross sectionof a powder dispenser 1911 with slanted bottom plane 1912 and a curvedadditional plane 1915. The powder dispenser may have a curved bottom.The powder dispenser may have one or more additional planes that are orare not slanted. The powder dispenser may have one or more additionalplanes that are parallel or perpendicular to the substrate. The radiusof curvature of the curved planes (or a vertical cross section thereof)may be situated below the curved plane (e.g., towards the direction ofthe substrate). FIG. 19C shows an examples of a vertical cross sectionof a powder dispenser 1921 with a curved bottom plane 1922 and a slantedadditional (extended) plane 1925. The radius of curvature r₁, r₂ and/orr₁₂ may be at least about 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7mm, 8 mm, 9 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm,90 mm, or 100 mm. The radius of curvature r₁, r₂ and/or r₁₂ may be atmost about 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm,10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100mm. The radius of curvature r₁, r₂ and/or r₁₂ may be of any valuebetween the afore-mentioned values (e.g., from 0.5 mm to about 100 mm,from about 0.5 mm to about 50 mm, from about 50 mm to about 100 mm).

In some examples, the power dispenser comprises both an exit openingport and at least a first slanted surface as delineated above. Forexample, the power dispenser can comprise both a side exit opening portand at least a first slanted surface as delineated above. The powerdispenser can comprise both a side exit opening and at least a firstslanted plane and a second slanted plane as delineated above. The one ormore slanted planes can reside at the bottom of the powder dispenser.The second plane can be an extension of the bottom of the powderdispenser. The second plane can be disconnected from the bottom of thepowder dispenser.

The opening of the powder dispenser can comprise a mesh or a plane withholes (collectively referred to herein as “mesh”, e.g., FIG. 16A, 1607).The mesh comprises a hole (or an array of holes). The hole (or holes)can allow the powder material to exit the powder dispenser. The hole inthe mesh can have a fundamental length scale of at least about 10 μm, 20μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 250μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700μm, 750 μm, 800 μm, 850 μm, 900 μm 950, μm, or 1000 μm. The hole in themesh can have a fundamental length scale of at most about 10 μm, 20 μm,30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm,130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 250 μm,300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm,750 μm, 800 μm, 850 μm, 900 μm 950, μm, or 1000 μm. The hole in the meshcan have a fundamental length scale of any value between theafore-mentioned fundamental length scales. For example, the hole in themesh can have a fundamental length scale from about 10 μm to about 1000μm, from about 10 μm to about 600 μm, from about 500 μm to about 1000μm, or from about 50 μm to about 300 μm. The fundamental length scale ofthe holes may be adjustable or fixed. In some embodiments the openingcomprises two or more meshes. At least one of the two or more meshes maybe movable. The movement of the two or more meshes may be controlledmanually or automatically (e.g., by a controller). The relative positionof the two or more meshes with respect to each other may determine therate at which the powder passes through the hole (or holes). Thefundamental length scale of the holes may be electrically controlled.The fundamental length scale of the holes may be thermally controlled.The mesh may be heated or cooled. The temperature of the mesh may becontrolled manually or by a controller. The holes of the mesh can shrinkor expand as a function of the temperature or electrical charge of themesh. The mesh can be conductive. The mesh may comprise a mesh ofstandard mesh number 50, 70, 90, 100, 120, 140, 170, 200, 230, 270, 325,550 or 625. The mesh may comprise a mesh of standard mesh number betweenany of the aforementioned mesh numbers. For example, the mesh maycomprise a mesh of standard mesh number from 50 to 625, from 50 to 230,from 230 to 625, or from 100 to 325. The standard mesh number may be USor Tyler standard.

The two meshes may have at least one position where no powder can passthough the exit opening. The two meshes may have a least one positionwhere a maximum amount of powder can pass though the exit opening. Thetwo meshes can be identical or different. The size of the holes in thetwo meshes can be identical or different. The shape of the holes in thetwo meshes can be identical or different. The shape of the holes can beany hole shape as described herein. FIG. 16C shows an example of apowder dispenser 1624 having an opening 1627 having two meshes or twoplanes with holes. FIG. 16C shows an example where the extensions of twomeshes 1622 and 1626 can be translated vertically.

The opening (e.g., port) of the powder dispenser can comprise a blade.The blade can be a “doctor's blade.” FIG. 16B shows an example of apowder dispenser 1614 having an opening comprising a “doctor's blade”1617. The blade can be any of the afore-mentioned blades. The openingmay comprise both a blade and a mesh or a plane with holes. The mesh (orplane with holes) may be closer to the exit opening than the blade. Theblade may be closer to the exit opening than the mesh (or plane withholes). The exit opening can comprise several meshes and blades. Theexit opening can comprise a first blade followed by a mesh that isfollowed by a second blade closest to the surface of the exit opening.The exit opening can comprise a first mesh followed by a blade, which isfollowed by a second mesh closest to the surface of the exit opening.The first and second blades may be identical or different. The first andsecond meshes may be identical or different. The powder dispenser maycomprise a spring at the exit opening. FIGS. 18A-D show examples ofpowder dispensers having an opening comprising a spring (e.g., 1807).

Any of the layer dispensing mechanisms described herein can comprise abulk reservoir (e.g., a tank, a pool, a tub, or a basin) of powder and amechanism configured to deliver the powder from the bulk reservoir tothe layer dispensing mechanism. The powder reservoir can be connected ordisconnected from the layer dispensing mechanism (e.g., from the powderdispenser). FIG. 15 shows an example of a bulk reservoir 1513, which isconnected to the powder dispenser 1509. FIG. 17 shows an example of abulk reservoir 1701, which is disconnected from the powder dispenser1702. The disconnected powder dispenser can be located above, below orto the side of the powder bed. The disconnected powder dispenser can belocated above the powder bed, for example above the powder entranceopening to the powder dispenser. The connected powder dispenser may belocated above, below or to the side of the powder exit opening port. Theconnected powder dispenser may be located above the powder exit opening.Powder material can be stored in the bulk reservoir. The bulk reservoirmay hold at least an amount of powder material sufficient for one layer,or sufficient to build the entire 3D object. The bulk reservoir may holdat least about 200 grams (gr), 400 gr, 500 gr, 600 gr, 800 gr, 1Kilogram (Kg), or 1.5 Kg of powder material. The bulk reservoir may holdat most 200 gr, 400 gr, 500 gr, 600 gr, 800 gr, 1 Kg, or 1.5 Kg ofpowder material. The bulk reservoir may hold an amount of materialbetween any of the afore-mentioned amounts of bulk reservoir material(e.g., from about 200 gr to about 1.5 Kg, from about 200 gr to about 800gr, or from about 700 gr to about 1.5 Kg). The powder dispenserreservoir may hold at least an amount of powder material sufficient forat least one, two, three, four or five layers. The powder dispenserreservoir may hold at least an amount of powder material sufficient forat most one, two, three, four or five layers. The powder dispenserreservoir may hold an amount of material between any of theafore-mentioned amounts of material (e.g., sufficient to a number oflayers from about one layer to about five layers). The powder dispenserreservoir may hold at least about 20 grams (gr), 40 gr, 50 gr, 60 gr, 80gr, 100 gr, 200 gr, 400 gr, 500 gr, or 600 gr of powder material. Thepowder dispenser reservoir may hold at most about 20 gr, 40 gr, 50 gr,60 gr, 80 gr, 100 gr, 200 gr, 400 gr, 500 gr, or 600 gr of powdermaterial. The powder dispenser reservoir may hold an amount of materialbetween any of the afore-mentioned amounts of powder dispenser reservoirmaterial (e.g., from about 20 gr to about 600 gr, from about 20 gr toabout 300 gr, or from about 200 gr to about 600 gr). Powder may betransferred from the bulk reservoir to the powder dispenser by anyanalogous method described herein for exiting of powder material fromthe powder dispenser. At times, the exit opening ports (e.g., holes) inthe bulk reservoir exit opening may have a larger fundamental lengthscale relative to those of the powder dispenser exit opening port. Forexample, the bulk reservoir may comprise an exit comprising a mesh or asurface comprising at least one hole. The mesh (or a surface comprisingat least one hole) may comprise a hole with a fundamental length scaleof at least about 0.25 mm, 0.5 mm. 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7mm, 8 mm, 9 mm or 1 centimeter. The mesh (or a surface comprising atleast one hole) may comprise a hole with a fundamental length scale ofat most about 0.25 mm, 0.5 mm. 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm,8 mm, 9 mm or 1 centimeter. The mesh (or a surface comprising at leastone hole) may comprise a hole with a fundamental length scale of anyvalue between the afore-mentioned values (e.g., from about 0.25 mm toabout 1 cm, from about 0.25 mm to about 5 mm, or from about 5 mm toabout 1 cm). The bulk reservoir may comprise a plane that may have atleast one edge that is translatable into or out of the bulk reservoir.The bulk reservoir may comprise a plane that may pivot into or out ofthe bulk reservoir (e.g., a flap door). Such translation may create anopening, which may allow powder in the reservoir to flow out of thereservoir (e.g., using gravity). A controller may be operatively coupledto the powder reservoir. The controller may control the amount of powderreleased from the bulk reservoir by controlling, for example, the amountof time the conditions for allowing powder to exit the bulk reservoirare in effect. A controller may control the amount of powder releasedfrom the powder dispenser by controlling, for example, the amount oftime the conditions for allowing powder to exit the powder dispenser arein effect. In some examples, the powder dispenser dispenses of anyexcess amount of powder that is retained within the powder dispenserreservoir, prior to the loading of powder from the bulk reservoir to thepowder dispenser reservoir. In some examples, the powder dispenser doesnot dispense of any excess amount of powder that is retained within thepowder dispenser reservoir, prior to loading of powder from the bulkreservoir to the powder dispenser reservoir. Powder may be transferredfrom the bulk reservoir to the powder dispenser using a scoopingmechanism that scoops powder from the bulk reservoir and transfers it tothe powder dispenser. The scooping mechanism may scoop a fixed orpredetermined amount of material. The scooped amount may be adjustable.The scooping mechanism may pivot (e.g., rotate) in the directionperpendicular to the scooping direction. The bulk reservoir may beexchangeable, removable, non-removable, or non-exchangeable. The bulkreservoir may comprise exchangeable parts. The powder dispenser may beexchangeable, removable, non-removable, or non-exchangeable. The powderdispensing mechanism may comprise exchangeable parts.

Powder in the bulk reservoir or in the powder dispensing mechanism canbe preheated, cooled, be at an ambient temperature or maintained at apredetermined temperature. A leveling mechanism (e.g., FIG. 11, 1103, arake, roll, brush, spatula or blade) can be synchronized with the powderdispensing mechanism to deliver the powder to the powder bed. Theleveling mechanism can level, distribute and/or spread the powder on thesubstrate (or on the base when the substrate comprises a base) as thepowder is dispensed by the mechanism.

In one example, the leveling mechanisms (e.g., powder levelingmechanism), and/or powder removal mechanisms described herein is able tolevel the top surface of the powder material in any method describedherein, without substantially altering the position of a hardenedmaterial that is disposed within the powder material and is suspended inthe powder material. The hardened material may be debris or at least apart (or portion) of a 3D object. The hardened material that issuspended (e.g., floating) in the powder material may not connect to theenclosure, the substrate or the base. The hardened material may not beenclosed in a scaffold that is suspended in the powder material. Thescaffold may be a filigree (e.g., a lace). The object may compriseauxiliary supports. The object suspended (e.g., floating) in the powdermaterial may not touch the enclosure, the substrate or the base. Theobject may comprise auxiliary supports. The auxiliary supports may besuspended in the powder material. The suspended (e.g., floating)auxiliary supports may not be connected to the enclosure, the substrateor the base. The suspended (e.g., floating) auxiliary supports may nottouch the enclosure, the substrate or the base. The leveling mechanismsmay be able to level the top surface of the powder bed while alteringthe position of an object (e.g., 3D object or debris) by a positionalteration value. The position alteration value may be at most about 1micrometer (μm), 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm,11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 25μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100μm, 200 μm, or 300 μm. The position alteration value may be any valuebetween the aforementioned values. For example, the position alterationvalue may be from about 1 μm to about 300 μm, from about 1 μm to about50 μm, from about 1 μm to about 20 μm, from about 1 μm to about 10 μm,from about 1 μm to about 50 μm, or from about 1 μm to about 100 μm.Altering the position may be shifting the position. The levelingmechanisms may be able to level the top surface of the powder materialwhile altering the position of a hardened material (e.g., 3D object ordebris) by at most 20 micrometer (μm). The leveling mechanisms may beable to level the top surface of the powder material while altering theposition of the hardened material by at most 10 micrometer (μm). Theleveling mechanisms may be able to level the top surface of the powdermaterial while altering the position of the hardened material by at most5 micrometer (μm). The alteration of the position may be horizontalalteration. The alteration of the position may be vertical alteration.The alteration of the position may be horizontal or vertical alteration.The alteration of the position may be both vertical and horizontal. Theobject may be a 3D object. The 3D object may be a substantially planarobject or a wire. The hardened material may comprise transformed powder(e.g., that was allowed to harden). The 3D object may be devoid ofauxiliary supports. The 3D object may comprise spaced apart auxiliarysupports as described herein. The leveling mechanism may level the layerof powder material while not substantially altering the position of thehardened material (e.g., suspended 3D object). Lack of substantialalteration may be relative to imaging, or image processing. Theresolution of the imaging or image processing may be at most about 1 μm,2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40μm, 50 μm, or 60 μm. The resolution of the imaging or image processingmay be at least about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, or 60 μm. The resolution of theimaging or image processing may of any value between the afore-mentionedresolution values (e.g., from about 1 μm to about 60 μm, from about 1 μmto about 10 μm, or from about 10 μm to about 60 μm). FIG. 21A shows anexample of two suspended planes 2101 and 2102 within a layer of powdermaterial before leveling by a leveling mechanism described herein, andtwo planes that are connected to a base 2103 and 2104 which serve asreference points. FIG. 21B shows an example of the two suspended planes(renumbered as 2111 and 2112 in FIG. 21B) after leveling by a levelingmechanisms described herein, and exposure by a soft blow of air from aposition above each of the planes. Planes 2111 and 2112 correspond tothe planes 2101 and 2102 respectively. Planes 2113 and 2114 correspondto 2103 and 2104, respectively, are attached to the base to serve asreference points.

The leveling member and/or the powder dispenser may travel at a speed ofat least about 10 millimeters per second (mm/s), 15 mm/s, 20 mm/s, 25mm/s, 30 mm/s, 35 mm/s, 40 mm/s, 45 mm/s, 50 mm/s, 70 mm/s, 90 mm/s, 100mm/s, 120 mm/s, 140 mm/s, 150 mm/s, 160 mm/s, 180 mm/s, 200 mm/s, 220mm/s, 240 mm/s, 260 mm/s, 280 mm/s, 300 mm/s, 350 mm/s, 400 mm/s, 450mm/s, or 500 mm/s. The leveling member and/or the powder dispenser maytravel at a speed of at most about 10 mm/s, 15 mm/s, 20 mm/s, 25 mm/s,30 mm/s, 35 mm/s, 40 mm/s, 45 mm/s, 50 mm/s, 70 mm/s, 90 mm/s, 100 mm/s,120 mm/s, 140 mm/s, 150 mm/s, 160 mm/s, 180 mm/s, 200 mm/s, 220 mm/s,240 mm/s, 260 mm/s, 280 mm/s, 300 mm/s, 350 mm/s, 400 mm/s, 450 mm/s, or500 mm/s. The leveling member and/or the powder dispenser may travel atany speed between the afore-mentioned speeds (e.g., from about 10 mm/sto about 500 mm/s, from about 10 mm/s to about 300 mm/s, or from about200 mm/s to about 500 mm/s). The leveling member and the powderdispenser may travel at identical speeds or at different speeds. Thetraveling speeds of the leveling member and/or the powder dispenser maybe controlled manually or automatically (e.g., by a controller). Thetraveling speed may refer the speed traveled across the powder bed(e.g., laterally).

The powder dispenser may dispense powder at an average rate of at leastabout 1000 cubic millimeters per second (mm³/s), 1500 mm³/s, 2000 mm³/s,2500 mm³/s, 3000 mm³/s, 3500 mm³/s, 4000 mm³/s, 4500 mm³/s, 5000 mm³/s,5500 mm³/s, or 6000 mm³/s. The powder dispenser may dispense powder atan average rate of at most about 1000 mm³/s, 1500 mm³/s, 2000 mm³/s,2500 mm³/s, 3000 mm³/s, 3500 mm³/s, 4000 mm³/s, 4500 mm³/s, 5000 mm³/s,5500 mm³/s, or 6000 mm³/s. The powder dispenser may dispense powder atan average rate between any of the afore-mentioned average rates (e.g.,from about 1000 mm³/s to about 6000 mm³/s, from about 1000 mm³/s toabout 3500 mm³/s, or from about 3000 mm³/s to about 6000 mm³/s).

The powder dispenser can comprise a rotating roll. The surface of theroll may be a smooth surface or a rough surface. Examples of rollsurfaces are shown in FIG. 17 and include a rough surface roll 1709,roll with protrusions 1707, roll with depression 1719. The surface ofthe roll may include depressions, protrusions or both protrusions anddepressions (e.g., FIG. 13B, 1313, or FIG. 17). The roll may be situatedsuch that at a certain position, the powder disposed above the roll(e.g. 1312 or 1703) is unable to flow downwards as the roll shuts theopening of the powder dispenser. When the roll rotates (either clockwiseor counter clockwise), a portion of the powder may be trapped within thedepressions or protrusions (or both), and may be transferred from thepowder occupying side of the powder dispenser, to the powder free sideof the powder dispenser. Such transfer may allow the powder to beexpelled out of the bottom of the powder dispenser (e.g., 1336) towardsthe powder bed (e.g., 1316). A similar mechanism is depicted in FIG. 13Dshowing an example of a powder dispenser that comprises an internal wallwithin (e.g., 1327). The powder transferred by the roll 1331, may bethrown onto the wall 1337, and may then exit the funnel (e.g., 1330)though the exit opening port.

The mechanism configured to deliver the powder material to the substratecan comprise a flow of gas mixed with powder particles. FIGS. 10A and10B show two example configurations of mechanisms configured to deliverthe powder to the substrate (e.g., from the reservoir). The mechanismconfigured to deliver the powder to the substrate can be an air knife.The air knife can be articulated by a scanner to deliver powder to atleast a fraction of the substrate (e.g., 904). The air knife can bearticulated by a scanner that is also used to articulate one or moreenergy sources included in the system. FIG. 10A depicts a schematic ofan air knife 1000 that can be configured to deliver the powder 1001 tothe substrate (e.g., from the reservoir). The air knife 1000 can delivera flow of gas and powder particles to the substrate. The powderparticles can be suspended in the gas. At least one fan 1002 can beincluded in the air knife to drive the flow of the gas and particles.The number density of the particles in the gas and the flow rate of thegas can be chosen such that a predetermined amount of powder isdispensed on to the substrate in a predetermined time period. The gasflow rate can be chosen such that gas blown onto the substrate does notdisturb a powder layer on the substrate and/or the three dimensionalobject. The gas flow rate can be chosen such that gas blown onto thesubstrate does not disturb at least the position of the threedimensional object.

FIG. 10B depicts a curved tube 1003 that can be another mechanismconfigured to deliver the powder from the reservoir to the substrate.The curved tube can comprise an opening 1004. The opening can be locatedat an inflection point of the curved tube shape. The opening can belocated on the outside of the curved tube shape. The opening can be on aside of the tube that is adjacent to the substrate 904. The opening 1004can be a pinhole. The pinhole can have a diameter or other maximumlength scale of at least about 0.001 mm, 0.01 mm, 0.03 mm, 0.05 mm, 0.07mm, 0.09 mm, 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 10 mm. A mixtureof gas and powder particles 1001 can be driven through the curved tube1003. The powder particles (i.e., particles of the powder material) canbe suspended in the gas. At least a fraction of the powder particles canexit the curved tube through the opening 1004 and dispensed onto thesubstrate 904. The number density of the particles in the gas and theflow rate of the gas can be selected such that a predetermined amount ofpowder is dispensed on to the substrate in a predetermined time period.The gas flow rate can be chosen such that gas blown onto the substratedoes not disturb a powder layer on the substrate and/or the threedimensional object. The distance 1005 between the opening and thesubstrate can be adjusted such that a predetermined amount of powder isdispensed on to the substrate in a predetermined time period. In somecases, the size of the opening can be selected such that particles in apredetermined size range exit the curved tube through the opening 1004and dispensed onto the substrate 904.

The powder dispensed onto the substrate by the leveling mechanism can bespread and/or leveled (e.g., a roll, see FIG. 12E at 1222). The levelingmember can be configured to level a layer of the powder on the substrate(e.g., 1223), to be substantially planar (e.g., horizontal) (e.g.,1221). The leveling member can comprise a set of extrusions (e.g., hardor soft extrusions) (e.g., FIG. 12F at 1227). The extrusion may have apointy, round or blunt end. The extrusions may be blades. The levelingmember can move at least a fraction of the powder without substantiallymoving the 3D object. In some examples, substantially moving the atleast portion of the 3D object comprises changing the position of the atleast part of the three dimensional object by the position alterationvalue delineated herein. Substantially moving the at least portion ofthe 3D object comprises changing the position of the at least part ofthe three dimensional object by the position alteration value. Theleveling member can move at least a fraction of the powder withoutsubstantially changing a location of the 3D object in the powder bed.

The leveling member can comprise a combination of a roller having arolling surface that comprises protrusions, depressions or bothprotrusions and depressions. In some examples, the roller has a rollingsurface that is smooth and does not have any protrusions or depressions(e.g., FIG. 12E at 1222). In some examples, the roller has a rollingsurface that is rough. In some examples, the roller comprisesdepressions. In some examples, the roller comprises protrusions (e.g.,12F at 1227). The roller can be in front of or behind a combingmechanism (e.g., comprising a rake, brush, spatula or knife). Thecombing mechanism may comprise a vertical cross section (e.g., sidecross section) of a circle, triangle, square, pentagon, hexagon,octagon, any other polygon, or an irregular shape. The roller can atleast partially level the powder layer before the powder layer isleveled by the combing mechanism. The rotation of the roller can be inthe direction in which the leveling member is moving (e.g., laterally),in the opposite direction in which the leveling member is moving, or anycombination of both the directions. The roller can be in communicationwith an active rotation mechanism (e.g., motor shaft) to effectuate therotation of the roller. The roller can rotate in a clockwise and/orcounter-clockwise direction. The roller can have a rolling surface witha static friction coefficient of at least about 0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9, or 1.0. The roller can have a rolling surface with adynamic friction coefficient of at least about 0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9, or 1.0. The roller can be a single roller. Theroller can comprise two or more rollers. The two or more rollers canrotate in the same or different directions, at the same or at differentrates. The rotation of the two or more rollers may be synchronized ornot synchronized. The rollers can be rotated passively, actively (e.g.,by a controller and power source), or any combination thereof. Therollers can be rotated manually or automatically (e.g., controlled by acontroller). The roller can have an eccentric rotation. A roller witheccentric rotation can permit multi-height planarization. The roller canvibrate. When the roller comprises more than one roller, at least afraction of the rollers can be configured to compress the powder and afraction of the rollers can be configured to level (e.g., planarize) thelayer of powder material. The surface (e.g., rolling surface) of thepowder bed that was leveled by the roller can be smooth, leveled, orboth. The surface of the roller can be rough. The surface of the rollercan comprise indentations (e.g., depressions), protrusions (e.g.,blades) or both. The blades can comprise one or more substantiallysmooth blades, sharp blades, or any combination thereof. A substantiallysmooth blade can have at least one cutting (e.g., shearing) surface withminimal amount of features protruding from the surface, or intrudinginto the surface (e.g., bumps or grooves). A substantially smooth bladecan have at least one cutting surface with features protruding from thesurface, or intruding into the surface, wherein the average distributionof the feature spans at most about 5 μm, 3 μm, 1 μm, 300 nm, 100 nm, 30nm, or 10 nm. The roller can be made of material that is rigid such thatthe roller does not deform when translating along a surface of thepowder material. In some cases, the rigid material can be metal (e.g.,elemental or alloy), hard plastic, ceramic, composite material, or anycombination thereof. In some cases, the roller can be made from amaterial that is flexible such that the roller at least partially deformwhen it translates along a surface of the powder. The flexible materialcan be metal foil, rubber, soft plastic, or any combination thereof.

The leveling mechanism can comprise a plurality of needles distributedacross an axis of a smoothing mechanism. The plurality of needles can bearranged in a matrix or rows and columns, in an array, in a pattern, orrandomly. The needles can be rigid, flexible or any combination thereof.The needles can be arranged on the leveling mechanism such that eachneedle in the plurality of needles contacts a different location on thebed of powder material. The plurality of needles can level and/or smooththe powder dispensed from the top-dispense powder dispenser. Leveling ofthe powder by the needles can arrange the powder such that the powderhas a planar uniformity in at least one plane. Leveling of the powdermaterial by the powder leveling mechanism and/or powder removingmechanism can result in a plane with a planar uniformity in at least oneplane. The planar uniformity can be in at least one plane (e.g.,horizontal plane). The planar uniformity can be at the top of the layerof powder material that is exposed. For example, the planar uniformitycan be at the top of the layer of powder material that is exposed to theenvironment in the enclosure (e.g., the gas within the chamber). Theaverage plane may be a plane defined by a least squares planar fit ofthe top-most part of the surface of the layer of powder material. Theaverage plane may be a plane calculated by averaging the powder heightat each point on the top surface of the powder bed. In some cases,either or both of a rake and a roller can be provided adjacent to theplurality of protrusions (e.g., extrusions).

In some cases an air knife can dispense powder ahead of the rake.Movement of the combing mechanism (e.g., rake) and the air knife can besynchronized or non-synchronized. Movement of the air knife and the rakecan be controlled by the same scanner or by different scanners.

In some instances, the leveling mechanism comprises a gas knife (e.g.,air knife) that shears or cuts the layer of powder material. Theleveling gas knife may comprise a concentrated or pressurized stream ofgas (e.g., air, H₂, He, or Ar). The blade of the leveling mechanism cancomprise the gas knife.

The combing mechanism (e.g., rake) can comprise one or more blades. FIG.11 depicts an example of a rake 1103 that can move powder along asubstrate. The combing mechanism can have one or more blades 1101 thatcontact the bed of powder material. The blades can have different sizesor a single substantially uniform size. The blades can extend away froma top 1102 of the rake different distances. The blades can be orientedat different angles (e.g., different angles of attack). The angle ofattack can be an angle of a surface of the blade relative to a surfaceof the powder. In some cases a shallow angles of attack can applyrelatively less pressure to the part relative to a steep angle ofattack. A shallow angle of attach can be an angle of at most about 45°,40°, 35°, 30°, 25°, 20°, 15°, 10°, or 5° between the surface of theblade and the average top surface of the powder layer. The shallow angleof attach may be about 0° between the surface of the blade and theaverage top surface of the powder layer. The blades can be provided in aseries on the combing mechanism, the series of blades can have anincreasing or decreasing angle of contact relative to each other. Theangles of the blades can be arranged in a pattern (e.g., in a line) orat random. In some cases the combing mechanism (e.g., rake) can comprisea plow. The powder level (e.g., layer thickness) ahead of the rake canbe actively or passively controlled.

The blades can be made of material that is rigid such that a bladewithin the combing mechanism does not move when translated along asurface of the powder. In some cases, the rigid material can be metal(e.g., elemental or alloy), hard plastic, ceramic, or any combinationthereof. In some cases, at least a fraction of the blades can be madefrom a material that is flexible such that the blades at least partiallydeform when dragged along a surface of the powder. The flexible materialcan be metal foil, rubber, soft plastic, or any combination thereof.

Any of the systems descried herein (collectively “the system”) maycomprise a powder dispensing mechanism, a powder leveling mechanism,powder removing mechanism a controller, or any combination thereof.

The controller may control the vibrator(s). The controller may controlthe operation of the vibrator(s). The controller may control theamplitude of vibrations of the vibrator(s). The controller may controlthe frequency of vibration of the vibrator(s). When the system comprisesmore than one vibrator, the controller may control each of themindividually, or as a group (e.g., collectively). The controller maycontrol each of the vibrators sequentially. The controller may controlthe amount of powder material released by the powder dispenser. Thecontroller may control the velocity of the powder material released bythe powder dispenser. The controller may control the height of powdermaterial depositing a layer of powder material (e.g., disposed in thepowder bed). The controller may control the height from which powder isreleased from the powder dispenser.

The controller may control the height of the leveling member. Thecontroller may control the height of leveling member blade. Thecontroller may control the rate of movement of the leveling member(e.g., the blade). The controller may control the position of the powderdispenser. The controller may control the position of the levelingmember. The position may comprise a vertical position, horizontalposition, or angular position. The position may comprise coordinates.

The controller may control the height of the powder removing member. Thecontroller may control the rate of movement of the powder removingmember. The controller may control the position of the powder removingmember. The position may comprise a vertical position, horizontalposition, or angular position. The position may comprise coordinates.The controller may control the amount of material removed by the powderremoving member. The controller may control the rate of material removedby the powder removing member.

The controller may control the path traveled by the powder dispensingmechanism, powder removal mechanism and/or the leveling mechanism. Thecontroller may control the leveling of a top surface of a layer ofpowder material deposited in the enclosure. For example, the controllermay control the final height of the newly deposited powder material. Thecontroller may control the final height of the powder material (e.g.,the last formed layer of powder material). In some embodiments, thepowder dispenser may deposit at least part of a layer of powder materialhaving a first vertical height. The leveling mechanism and/or powderremoving mechanism may level the deposited powder material such that thevertical height of the leveled section of the layer of powder materialmay be at least about 0.02*, 0.04*, 0.05*, 0.06*, 0.08*, 0.1*, 0.2*,0.3*, 0.4*, 0.5*, 0.6*, 0.7*, 0.8*, or 0.9 times (*) the first verticalheight. The leveling member may level the deposited powder material suchthat the vertical height of the leveled section of the layer of powdermaterial may be at most about 0.02*, 0.04*, 0.05*, 0.06*, 0.08*, 0.1*,0.2*, 0.3*, 0.4*, 0.5*, 0.6*, 0.7*, 0.8*, or 0.9 times (*) the firstvertical height. The leveling member may level the deposited powdermaterial such that the vertical height of the leveled section of thelayer of powder material may be a product of any value between the aforementioned multiplier values (e.g., from about 0.02* to about 0.9*, fromabout 0.02* to about 0.5*, from about 0.4* to about 0.9*, or from about0.05* to about 0.4*).

Described herein are methods for generating 3D object from a powdermaterial, comprising leveling powder material utilizing any of theapparatuses described herein. The powder material may be powder materialdisposed adjacent to (e.g., above) the bottom of the enclosure, thesubstrate or the base. The powder material may have been deposited bythe layer dispensing mechanism (e.g., powder dispenser). Describedherein is a method for generating 3D object from a powder materialcomprising dispensing the powder material towards the bottom of anenclosure (e.g., towards the substrate or the base) utilizing anyapparatus described herein. Described herein is a method for generating3D object from a powder material comprising dispensing the powdermaterial towards the bottom of an enclosure (e.g., towards the substrateor the base) utilizing any of the layer dispensing mechanisms (e.g.,powder dispenser) described herein. The method may comprise dispensing alayer of powder material. The method may comprise translating theapparatus, the layer dispensing mechanism, the powder dispensingmechanism, the leveling mechanism, the powder removing mechanism, thesubstrate, the base, the enclosure, or any combination thereof. Thecontroller may control the translation. The powder material may bedispensed by the layer dispensing mechanism (e.g., the powder dispenser)when the layer dispensing mechanism travels in a first direction. Thepowder material may be leveled by the leveling mechanism when theleveling mechanism and/or powder removing mechanism travels in a seconddirection. The first and second direction may be the same direction. Thefirst and second direction may be opposite directions.

The method may comprise vibrating at least part of the powder material,at least part of the powder dispensing mechanism, or at least part ofthe layer dispensing mechanism. The at least part of the powderdispensing mechanism may comprise vibrating at least part of the exitopening of the powder dispensing mechanism. The method may comprisevibrating the powder in the powder bed to level the powder material. Themethod may comprise vibrating the enclosure, the substrate, the base,the container that accommodates the powder bed, or any combinationthereof, to level the powder material. The vibrations may be ultrasonicvibrations.

The method may comprise leveling at least part of a layer of powdermaterial using the leveling mechanism. The leveling may be able to levelthe top surface of the powder material with a deviation from the averageplane created by the top surface. The deviation from the average planemay be of any deviation from average plane value disclosed herein. Theleveling may displace an object by the position alteration valuedisclosed herein.

In some cases, a surface of the powder layer can be maintained withsubstantially average planar uniformity by fluidizing the powder in thepowder bed. The fluidized powder bed can have one or more properties ofa liquid (e.g., with a similar volume as the volume of the powder bed).The fluidized powder bed can exhibit hydrostatic behavior such that aplanar uniform powder surface is maintained without a combing mechanism(e.g., leveling or smoothing). A fluidized bed can be generated in thepowder bed by forcing a pressurized gas through the powder bed. The gascan be flowed from the bottom, top or side of the powder bed. The gascan be an inert gas. The gas can be a noble gas. The gas can compriseargon, nitrogen, helium, neon, krypton, xenon, hydrogen, carbonmonoxide, carbon dioxide, or air. The gas in the fluidized bed can bethe same gas that is used in the chamber, or a different gas than theone used in the chamber.

At least a portion of the 3D object can sink in the fluidized bed. Atleast a portion of the 3D object can be surrounded by the fluidized bed(e.g., submerged). At least a portion of the 3D object can rest in thepowder material without substantial sinking (e.g., vertical movement).Lack of substantial sinking can amount to a sinking (e.g., verticalmovement) of at most about 40%, 20%, 10%, 5%, or 1% layer thickness.Lack of substantial sinking can amount to at most about 100 μm, 30 μm,10 μm, 3 μm, or 1 μm. At least a portion of the 3D object can rest inthe powder material without substantial movement (e.g., horizontalmovement, movement at an angle). Lack of substantial movement can amountto at most 100 μm, 30 μm, 10 μm, 3 μm, 1 μm, or less. The 3D object canrest on the substrate when the 3D object is sunk or submerged in thefluidized powder bed.

The methods described may comprise a powder leveling method wherein thepowder comprises a structure that protrudes from the exposed surface ofthe powder bed (i.e., the top surface of the powder bed). The structuremay be a powder material that was transformed and subsequently hardened.The structure may be a 3D object, part of a 3D object, or a powdermaterial that was transformed and subsequently hardened but did not forma part of the 3D object (i.e., debris). The height (i.e., verticaldistance) of the protruding structure from the exposed (i.e., top)surface of the powder bed may be at least about 10 μm, 30 μm, 50 μm, 70μm, 100 μm, 130 μm, 150 μm, 170 μm, 200 μm, 230 μm, 250 μm, 270 μm, or300 μm. The height of the protruding structure (herein after“protrusion”) from the top surface of the powder bed may be at mostabout 30 μm, 50 μm, 70 μm, 100 μm, 130 μm, 150 μm, 170 μm, 200 μm, 230μm, 250 μm, 270 μm, 300 μm, or 1000 μm. The height of the protrusionfrom the top surface of the powder bed may be between any of theaforementioned values. For example, from about 10 μm to about 1000 μm,from about 50 μm to about 100 μm, from about 30 μm to about 300 μm, fromabout 20 μm to about 400 μm, or from about 100 μm to about 900 μm. Theterm “between” as used herein is meant to be inclusive unless otherwisespecified. For example, between X and Y is understood herein to meanfrom X to Y.

In some examples, the method comprises depositing a layer of powdermaterial on the powder bed comprises dispensing the powder material intothe enclosure to provide a powder bed; generating the 3D object from aportion of the powder material by transforming the powder material intoa transformed material that subsequently forms a hardened material,wherein the hardened material protrudes from the top surface of thepowder bed, wherein the hardened material is movable within the powderbed; and adding a layer of powder material on the top surface of thepowder bed. The movable hardened material may comprise auxiliarysupports. The movable hardened material may be devoid of auxiliarysupports. In some examples, the hardened material is suspended in thepowder bed. In some examples, the hardened material comprising theauxiliary supports is suspended in the powder bed. In some examples, thehardened material is anchored (e.g., by auxiliary supports) to theenclosure. The anchors may be connected to the bottom or sides of theenclosure. The anchors may be connected to the substrate or to the base.The anchors may be the substrate, the base, the bottom of the enclosure,a scaffold structure, a sintered structure (e.g., a lightly sinteredstructure), or a mold (a.k.a., a mould).

In some example, adding a layer of powder material on the top surface ofthe powder bed displaces the hardened material by the positionalteration value. In some example, adding a layer of powder material onthe top surface of the powder bed displaces the hardened material byabout 20 micrometers or less. In some examples, the hardened materialcomprises warping, buckling, bending, rolling, curling, bulging, orballing. For example, the hardened material can include at least a partof a 3D object that was deformed. The deformation may be any deformationdisclosed herein such as warping, buckling, bulging, bending, rolling,curling or balling.

In some examples, the adding further comprises, using a powder dispenserto deposit the layer of powder material in the powder bed (e.g., by anydeposition method or mechanism described herein). In some examples, thetop surface of the added layer of powder material is substantiallyplanar. In some examples, the top surface of the added layer of powdermaterial is leveled to become substantially planar. The leveling maycomprise a leveling mechanism and/or a powder removal mechanism asdescribed herein. For example, the leveling of the top surface of thelayer of powder material may comprise shearing an excess amount of thepowder material. The shearing may include shearing with a knife (e.g., ahard, flexible or air knife as described herein). In some instances, thesheared powder material (i.e., the excess powder material) is displacedto another position in the powder bed. In some instances, the shearedpowder material (i.e., the excess powder material) is not displaced toanother position in the powder bed. For example, the excess powdermaterial may be removed by the powder removal mechanism describedherein. The removal of the powder material may comprise contacting thepowder bed (e.g., the top surface of the powder bed). The removal of thepowder material may exclude contacting the powder bed (e.g., the topsurface of the powder bed). For example, the adding may comprise using apowder removal member to remove the excess amount of powder materialwithout contacting the layer of powder material.

In some examples, the powder material, the hardened material, or bothare devoid of at least two metals that are present at a ratio that formsa eutectic alloy. In some examples, the powder material, the hardenedmaterial, or both are made of a single elemental metal. In someexamples, the powder material, the hardened material, or both include atmost substantially a single elemental metal composition. In someexamples, the powder material, the hardened material, or both are madeof a single metal alloy. In some examples, the powder material, thehardened material, or both include at most substantially a single metalalloy composition.

In another aspect described herein is a system for generating a threedimensional object, comprising: an enclosure that accommodates a powderbed comprising powder material; an energy source that provides an energybeam to the powder material, and thereby transforms the powder materialinto a transformed material that subsequently hardens to form a hardenedmaterial. The hardened material can protrude from the top surface of thepowder bed forming the protrusion described herein. The systemsdisclosed herein may further comprise a layer dispensing mechanismconfigured to add a planar powder layer into the powder bed. The layerdispensing mechanism may include the powder depositing mechanism. Thelayer dispensing mechanism may further include the powder levelingmechanism and/or the powder removing mechanism. The powder levelingmechanism (e.g., member) that levels an excess of powder material fromthe powder bed, may do so with or without contacting the powder bed. Thepowder leveling mechanism disclosed herein may be configured to at leastshear, shave, clip, trim, crop, cut, scrape, pare, or cutoff an excessof the powder material from a top (i.e., exposed) portion of the powderbed. The powder leveling member may displace the excess amount of powdermaterial to another position in the powder bed. In some instances, thepowder leveling member may not displace the excess amount of powdermaterial to another position in the powder bed.

The powder leveling mechanism may by any powder leveling mechanismdisclosed herein. The layer dispensing mechanism may comprise a powderremoval mechanism (e.g., member) that removes the excess of powdermaterial from the top portion of the powder bed with or withoutcontacting the top portion of the powder bed. The layer dispensingmechanism may comprise a powder removal mechanism (e.g., member) thatremoves the excess of powder material from the top portion of the powderbed while contacting the top portion of the powder bed. The layerdispensing mechanism may comprise a powder removal mechanism thatremoves the excess of powder material from the top portion of the powderbed without contacting the top portion of the powder bed. The layerdispensing mechanism may be separated from the top portion of the powderbed by a gap. The gap may be any gap disclosed herein. The powderremoval mechanism may be any powder removing mechanism described herein.The powder removal mechanism may be coupled or not coupled to the powderleveling mechanism. The powder removal mechanism may be coupled or notcoupled to the powder dispensing mechanism. The powder levelingmechanism may be coupled or not coupled to the powder dispensingmechanism.

The excess of powder material that was removed by the powder removalmechanism may be reused by the powder dispensing member. Reused mayinclude continuously reused during the operation of the layer dispensingmechanism, reused after a layer of powder material is added into thepowder bed, reused at a whim, reused manually, reused automatically,reused after a 3D object is generated.

The systems described herein may further comprise a controlleroperatively coupled to the energy source and to the layer dispensingmechanism or to at least one of its components. The controller may beprogrammed to (i) receive instructions to generate the three-dimensionalobject, (ii) generate the hardened material from a portion of the powdermaterial, and (iii) direct the layer dispensing mechanism to add a layerof powder material into the powder bed. The added layer of powdermaterial may have a top surface that is substantially planar. The addedlayer of powder material may have a top surface that is substantiallynon-planar. In some instances, the layer dispensing mechanism maydisplace the hardened material. In some instances, the layer dispensingmechanism may substantially not displace the hardened material. In someinstances, the layer dispensing mechanism may displace the hardenedmaterial by the position alteration value disclosed herein. In someinstances, the layer dispensing mechanism may displace the hardenedmaterial by at most 20 μm. The displacement may be vertical, horizontal,or angular displacement. The angular displacement may be a planar angleor a compound angle.

The controller may be operatively coupled to the powder dispensingmechanism (e.g., powder dispensing member, or powder dispenser) and maybe programmed to direct the powder dispensing mechanism to add the layerof powder material into the powder bed. The controller may beoperatively coupled to the powder leveling mechanism and may beprogrammed to level a top surface of the powder bed. The controller maybe operatively coupled to the powder removal member and may beprogrammed to regulate the removal of the excess of powder material. Thecontroller may control the recycling of the powder material that wasremoved by the powder removal mechanism. The controller can regulate anamount of the powder material that is dispensed by the powder dispensingmember.

The system may further comprise one or more mechanical membersoperatively coupled to the powder dispensing member, wherein the one ormore mechanical members subject the powder dispensing member tovibration. The mechanical members may be motors (e.g., rotary motors),or sonicators. The mechanical members may cause vibrations. Thecontroller may be operatively coupled to the one or more mechanicalmembers. The controller may be operatively coupled to the one or morevibrators. The controller may be programmed to control the one or moremechanical members to regulate an amount of the powder material that isdispensed by the powder dispensing member into the enclosure.

In another aspect, the methods described herein may comprise methods inwhich a layer of powder material is deposited in an enclosure to form apowder bed, at least part of the layer is hardened to form a hardenedmaterial (which may or may not comprise at least a part of the 3Dobject), the hardened material may or may not protrude from the exposedsurface of the powder bed. A second layer of powder material isdeposited in excess. The exposed surface of this second layer may or maynot be leveled. The leveling of the second layer may take place in twodistinct operations. The first one involves usage of the powder levelingmechanism, and the second one involves the usage of the powder removalmechanism. In some embodiments, the leveling of the second layer mayinvolves usage of both the powder leveling mechanism and the powderremoval mechanism in a single operation. In some embodiments, theleveling of the second layer may involves usage of the powder levelingmechanism closely followed by the powder removal mechanism. In someembodiments, depositing the second layer of powder material by thepowder deposition mechanism, leveling it by the leveling mechanism(e.g., shearing) and removing the powder by the powder removalmechanism, are conducted one after another in one lateral run. Forexample, the three mechanisms may closely follow each other. Forexample, at least two of the three mechanisms may closely follow eachother. For example, the three mechanisms may be integrated in onemechanism. For example, at least two of the three mechanisms may beintegrated in one mechanism. The mechanism(s) may spread and/or levelthe powder in the entire powder bed, or in only a portion of the powderbed. The method may include spreading and leveling the powder bed as themechanism(s) travel laterally in one direction. The method may includespreading the powder bed as the mechanism(s) travel laterally in a firstdirection, leveling as the mechanism(s) travel in the oppositedirection, and finally removing as the mechanism(s) again go in thefirst direction. The method may include operation of one or twomechanisms as the mechanism(s) travel laterally in a first direction,and operation of one or two mechanisms as the mechanism(s) travellaterally in the opposite direction. The mechanisms may include thepowder dispensing mechanism, the powder leveling mechanism, and thepowder removal mechanism. The method may spread and level the powdermaterial without substantially altering the position of the hardenedmaterial, whether or not it is anchored (e.g., by auxiliary supports).

In another aspect described herein are methods for generating athree-dimensional object relating to the deposition and leveling of alayer of powder material, wherein the final leveling operations takesplace without contacting the top surface of the powder bed. The methodcomprises providing a first layer of powder material into an enclosureto provide a powder bed having a first top surface (the first topsurface is at this stage the exposed surface); generating at least aportion of the three-dimensional object from at least a portion of thepowder material; dispensing a second layer of powder material onto thepowder bed, wherein the second layer of powder material comprises asecond top surface (the second top surface is at this stage the exposedsurface); removing (e.g., shearing) the second layer of powder materialto form a first planar surface; and removing substantially all thepowder material that is above a predetermined second planar surface fromthe second layer of powder material, wherein the removing occurs withoutcontacting the powder bed. The first planar surface can be at or belowthe lowest point of the second top surface. The second planar surfacecan be located below the first planar surface. The removing operationsmay comprise any powder removal method utilized by the powder removalsystem described herein.

The generating operation can comprise transforming the powder materialto generate a transformed material that subsequently hardens to form ahardened material, wherein at least a portion of the hardened materialprotrudes from the first top surface, thus forming a protrusion. In someinstances, the first layer of powder material is provided on a powderbed. In some instances, the first layer of powder material comprises theprotrusion. The protrusion can be any protrusion described herein (e.g.,at least a part of the 3D object, or a debris). The protrusion maycomprise warping, bending, bulging, curling, rolling, or balling of thehardened material. The height (i.e., vertical distance) of theprotruding structure from the exposed (i.e., top) surface of the powderbed may be any of the protrusion values disclosed herein. In someexamples, the second planar surface is situated above the first topsurface.

FIGS. 26A-D show examples of various stages of a layering methoddescribed herein. FIG. 26A shows a powder bed 2601 in which a (bent) 3Dobject 2603 is suspended in the powder bed, and is protruding from theexposed (top) surface of the powder bed by a distance 2605. The exposedsurface of the powder bed can be leveled (e.g., as shown in FIG. 26A,having a leveled plane 2604), or not leveled. FIG. 26B shows asucceeding operation where a layer is deposited in the powder bed (e.g.,above the plane 2604). The newly deposited layer may not have a leveledtop surface (e.g., 2608). The unleveled top surface 2608 includes alowest vertical point 2609. The plane 2606 is a plane that is situatedat or below the lowest vertical point of the unleveled surface, and ator above the protruding height 2605. The plane 2606 is located higherthan the top surface 2604 by a height 2610. FIG. 26C shows a succeedingoperation where the layer is leveled to the vertical position of theplane 2606 by a leveling mechanism. That leveling can be shearing of thepowder material. That leveling may not displace the excess of powdermaterial to a different position in the powder bed. FIG. 26D shows asucceeding operation where the leveled layer is leveled to a lowervertical plane level that is above 2604 and below 2606, and isdesignated as 2611. This second leveling operation may be conducted bythe powder removal mechanism, which may or may not contact the exposedlayer of the powder bed. This second leveling operation may or may notexpose the protruding object. This second leveling operation may be ahigher fidelity leveling operation. The average vertical distance fromthe first top surface to the second planar surface can be at least about5 μm, 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400μm, 450 μm, or 500 μm. The average vertical distance from the first topsurface to the second planar surface can be at most about 700 μm, 500μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 50μm, 10 μm, or 5 μm. The average vertical distance from the first topsurface to the second planar surface can be between any of theafore-mentioned average vertical distance values. The average verticaldistance from the first top surface to the second planar surface can befrom about 5 μm to about 500 μm, from about 10 μm to about 100 μm, fromabout 20 μm to about 300 μm, or from about 25 μm to about 250 μm.

The average vertical distance from the first top surface to the secondtop surface can be at least about 5 μm, 10 μm, 50 μm, 100 μm, 150 μm,200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 1000 μm, or 1500μm. The average vertical distance from the first top surface to thesecond top surface can be at most about 2000 μm, 1500 μm, 1000 μm, 700μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100μm, 50 μm, 10 μm, or 5 μm. The average vertical distance from the firsttop surface to the second top surface can be between any of theafore-mentioned average vertical distance values. For example, theaverage vertical distance from the first top surface to the second topsurface can be from about 5 μm to about 2000 μm, from about 50 μm toabout 1500 μm, from about 100 μm to about 1000 μm, or from about 200 μmto about 500 μm.

The average vertical distance from the first top surface to the firstplanar surface can be at least about 5 μm, 10 μm, 50 μm, 100 μm, 150 μm,200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, or 1000 μm. Theaverage vertical distance from the first top surface to the first planarsurface can be at most about 1000 μm, 700 μm, 500 μm, 450 μm, 400 μm,350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 50 μm, 10 μm, or 5 μm.The average vertical distance from the first top surface to the firstplanar surface can be between any of the afore-mentioned averagevertical distance values. The average vertical distance first topsurface to the first planar surface can be from about 5 μm to about 1000μm, from about 50 μm to about 500 μm, from about 10 μm to about 100 μm,from about 20 μm to about 300 μm, or from about 25 μm to about 250 μm.

The removing comprises any methodology used herein by the powder removalmechanism. For example, the removing operation may comprise usingvacuum. The removed powder material may be recycled or reused asdescribed herein. For example, the removed (i.e., excess) powdermaterial may be continuously reused in any of the methods describedherein.

The dispensing method may utilize any of the powder dispensing mechanismdescribed herein. For example, a dispensing method that utilizesgravitational force, and/or one that uses gas flow (e.g., airflow) thatdisplaces the powder material.

In another aspect described herein are systems for generating a threedimensional object, comprising an enclosure that accommodates a powderbed; an energy source that provides an energy beam to the powdermaterial, and thereby transforms the powder material into a transformedmaterial that subsequently hardens to form a hardened material; a powderdispensing member that dispenses the powder material into the powderbed; a powder leveling member that levels an exposed surface of thepowder bed; a powder removing member that removes powder material froman exposed surface of the powder bed without contacting the top surfaceof the powder bed; and a controller operatively coupled to the energysource, the powder dispensing member, the powder leveling member, andthe powder removing member, and is programmed to: direct the powderdispenser to dispense a first layer of the powder material having afirst top surface into the powder bed, receive instructions to generateat least part of the three-dimensional object, generate the at leastpart of the three-dimensional object from a portion of the powdermaterial, direct the powder dispenser to dispense a second layer ofpowder material having a second top surface adjacent to the first topsurface, direct the powder leveling mechanism (e.g., member) to levelthe second top surface to a first planar surface that is at or below thelowest point of the second top surface, and direct the powder removingmechanism (e.g., member) to remove an excess of powder material from thesecond layer to a predetermined second planar surface, wherein thesecond planar surface is below the first planar surface. The hardenedmaterial may form at least a part of the 3D object, or be a debris. Thesecond planar surface may be situated above the first top surface. Thepowder dispensing member may be separated from the exposed surface ofthe powder bed by a gap. The gap may be any gap disclosed herein. Theheight (vertical distance) of the gap may be any gap height disclosedherein. For example, the gap distance is from about 10 μm to about 50mm. The powder leveling mechanism and/or powder evacuating mechanism maydisplace the hardened material (e.g., 3D object) by about 300micrometers or less. The powder leveling mechanism and/or powderevacuating mechanisms may be able to level the top surface of the powderbed while altering the position of the hardened material by at mostabout 1 micrometer (μm), 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm,10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90μm, 100 μm, 200 μm, or 300 μm. The powder leveling mechanism and/orpowder evacuating mechanisms may be able to level the top surface of thepowder bed while altering the position of the hardened material by anyvalue between the aforementioned values. For example, the powderleveling mechanisms and/or powder removing mechanism may be able tolevel the top surface of the powder material while altering the positionof the hardened material by a distance of from about 1 μm to about 300μm, from about 1 μm to about 50 μm, from about 1 μm to about 20 μm, fromabout 1 μm to about 10 μm, from about 1 μm to about 50 μm, or from about1 μm to about 100 μm.

The system described herein (e.g., 900) can comprise a recycling system(e.g., 907). The recycling system can collect unused powder material andreturn the unused powder material to a reservoir of a powder dispensingmechanism, or to the bulk reservoir. At least a fraction of the powdermaterial pushed away by the translating mechanism (e.g., combingmechanism and/or roller) can be recovered by the recycling system. Avacuum (e.g., 908, which can be located at an edge of the powder bed)can collect unused powder. Unused powder can be removed from the powderbed without vacuum. Unused powder can be removed from the powder bed byactively pushing it from the powder bed (e.g., mechanically or using apositive pressurized gas). A gas flow (e.g., 909) can direct unusedpowder to the vacuum. A powder collecting mechanism (e.g., a shovel) candirect unused powder to exit the powder bed (and optionally enter therecycling system). The recycling system can comprise one or more filtersto control a size range of the particles returned to the reservoir.

In some cases, unused powder can be collected by a Venturi scavengingnozzle. The nozzle can have a high aspect ratio (e.g., at least about2:1, 5:1, 10:1, 20:1, 30:1, 40:1, or 100:1) such that the nozzle doesnot become clogged with powder particle(s). The nozzle can be alignedwith one or more energy beams emitted (e.g., from the primary and/orcomplementary energy source). For example, the nozzle and the one ormore energy beams can be aligned such that the energy source(s) cantravel through the nozzle opening when heating the powder layer. Thenozzle can collect unused powder as the energy beam is traveling throughthe nozzle to heat the powder layer.

In some cases, powder can be collected by one or more nozzles and/orvacuum suction ports provided on or adjacent to a heat transfer member,such as a cooling member (e.g., cooling plate), heating member or a heatstabilizing member (e.g., thermostat). The nozzles and/or vacuum suctionports can be mechanically coupled to the heat transfer member.

In some embodiments, the powder may be collected by a drainage systemthough one or more drainage ports that drain powder from the powder bedinto one or more drainage reservoirs. The powder in the one or moredrainage reservoirs may be re used (e.g., after filtration and/orfurther treatment).

The system components described herein can be adapted and configured togenerate a 3D object. The 3D object can be generated through a 3Dprinting process. A first layer of powder can be provided adjacent to abase, substrate or bottom of an enclosure. A base can be a previouslyformed layer of the 3D object or any other surface upon which a layer orbed of powder is spread, held, placed, or supported. In the case offormation of the first layer of the 3D object the first powder layer canbe formed in the powder bed without a base, without one or moreauxiliary support features (e.g., rods), or without any other supportingstructure other than the powder. Subsequent layers can be formed suchthat at least one portion of the subsequent layer melts, sinters, fuses,binds and/or otherwise connects to the at least a portion of apreviously formed layer. In some instances, the at least a portion ofthe previously formed layer that is transformed and subsequently hardensinto a hardened material, acts as a base for formation of the 3D object.In some cases the first layer comprises at least a portion of the base.The material of the powder can be any material used for 3D printingdescribed herein. The powder layer can comprise particles of homogeneousor heterogeneous size and/or shape.

FIG. 3 depicts an example of a bed 301 having a partially formed 3Dobject 302. The partially formed 3D object 302 can comprise at least onelayer that was previously transformed and hardened into the 3D object302. A first layer of powder 303 can be provided adjacent to partiallyformed 3D object 302. The first layer of powder 303 can be provided at afirst temperature (T₁). The first temperature can be substantially closeto the ambient temperature. In some cases the first layer can have afirst temperature (T₁) that is above or below room temperature. Forexample, the first temperature (T₁) can be at least about 0° C., 5° C.,10° C., 15° C., 20° C., 25° C., 30° C., 35° C., 40° C., 45° C., 50° C.,60° C., 70° C., 80° C., 90° C., 100° C., 200° C., 300° C., 400° C., or500° C. The first temperature (T₁) can be at most about 0° C., 5° C.,10° C., 15° C., 20° C., 25° C., 30° C., 35° C., 40° C., 45° C., 50° C.,60° C., 70° C., 80° C., 90° C., 100° C., 200° C., 300° C., 400° C., or500° C. The first temperature can be any value between theafore-mentioned temperature values (e.g., from about 0° C. to about 500°C., from about 0° C. to about 300° C., from about 200° C. to about 500°C., or from about 100° C. to about 400° C.). In some cases the firsttemperature (T₁) can be below 0° C.

Energy from a first (or primary) energy source 304 can be provided to atleast a portion of the first layer of powder 303. Energy from the firstenergy source 304 can be provided to the portion of the first layer ofpowder (e.g., using a vector scanning technique). In some cases, theprimary energy source can be a laser. In some cases, the primary energysource can project a radiation comprising electromagnetic, electron,positron, proton, plasma, or ionic radiation. The electromagnetic beammay comprise microwave, infrared (IR), ultraviolet (UV) or visibleradiation. The ion beam may include a cation or an anion. Theelectromagnetic beam may comprise a laser beam. The primary energysource may include a laser source. The primary energy source may includean electron gun or any other energy source configured to providetargeted energy to a surface or base. The primary energy source cancomprise a direct laser diode fiber coupled to a laser. The energyprovided to the portion of the first layer of powder can be absorbed bythe powder and the powder can experience and increase in temperature asa result of the absorption of energy. The energy provided by the primaryenergy source can fuse, sinter, melt, bind or otherwise connect one ormore portions of a previously solidified layer. Melting of thepreviously solidified layer and the powder material can merge (e.g.,fuse, sinter, melt, bind or otherwise connect) the two together to formthe 3D object. In some cases the primary energy source can melt at leastabout 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or100 layers of the previously solidified layer. A layer can have athickness of at least about 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30μm, 35 μm, 40 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, or 750 μm.In some cases the first energy source can be a beam of laser light. Thelaser light can have a power per unit area that is lower than or equalto the power per unit area of the second energy source. The laser lightcan have a power per unit area that is higher than the power per unitarea of the second energy source. The rise in temperature can besufficient to transform at least a portion of the first layer of powder.The rise in temperature can be sufficient to melt at least a portion ofa first layer of powder and allow the molten powder to remain molten forat least about 1 femtosecond (fs), 50 fs, 100 fs, 500 fs, 1 picosecond(ps), 50 ps, 100 ps, 500 ps, 1 nanosecond (ns), 50 ns, 100 ns, 500 ns, 1microsecond (p), 50 μs, 100 μs, 500 μs, 1 millisecond (ms), 50 ms, 100ms, or 500 ms. The rise in temperature can be sufficient to melt theentire first layer of powder. The rise in temperature can be sufficientto sinter at least a portion first layer of powder in at least 1femtosecond (fs), 50 fs, 100 fs, 500 fs, 1 picosecond (ps), 50 ps, 100ps, 500 ps, 1 nanosecond (ns), 50 ns, 100 ns, 500 ns, 1 microsecond (p),50 μs, 100 μs, 500 μs, 1 millisecond (ms), 50 ms, 100 ms, or 500 ms. Therise in temperature can be sufficient to sinter at least a portion firstlayer of powder in a period of time between the aforementioned periodsof time (e.g., from about 1 fs to about 500 ms, from about 1 ns to about500 ms, from about 1 fs to about 50 ns, or from about 1 ps to about 1ms). The rise in temperature can be sufficient to sinter the entirefirst layer of powder. The first layer of powder can be melted along apredetermined pattern or at random. Upon melting the first layer ofpowder can be at a second temperature (T₂). The second temperature (T₂)can be greater than the first temperature (T₁). The second temperature(T₂) can be lower than the first temperature (T₁). The secondtemperature (T₂) can be substantially equal to the first temperature(T₁). For example, the second temperature (T₂) can be at least about500° C., 750° C., 1000° C., 1250° C., 1500° C., 1750° C., 2000° C.,2250° C., 2500° C., 2750° C., 3000° C., 3500° C., 4000° C., or 5000° C.The second temperature can be any value between the afore-mentionedtemperature values (e.g., from about 500° C. to about 2500° C., fromabout 2250° C. to about 5000° C., or from about 1500° C. to about 3500°C.).

The primary energy source can deliver energy to at least one point in afirst layer of powder during a fixed time period. The fixed time periodcan be chosen such that a specified volume of the powder may reach atarget temperature. The time period can be chosen based on the thermalproperties of the powder material and the amount of energy provided bythe primary energy source. The fixed time period can be at least about 1femtosecond (fs), 50 fs, 100 fs, 500 fs, 1 picosecond (ps), 50 ps, 100ps, 500 ps, 1 nanosecond (ns), 50 ns, 0.1 microseconds (μs), 0.5 μs, 1.0μs, 2.0 μs, 3.0 μs, 4.5 μs, 5.0 μs, 10 μs, 20 μs, 50 μs, 100 μs, 300 μs,500 μs, or 1 ms. The fixed time period can be at most about 0.1microseconds (μs), 0.5 μs, 1.0 μs, 2.0 μs, 3.0 μs, 4.5 μs, 5.0 μs, 10μs, 20 μs, 50 μs, 100 μs, 300 μs, 500 μs, or 1 ms. The fixed time periodcan be any value between the above-mentioned values (e.g., from about 1fs to about 1 ms, from about 1 μs to about 500 μs, from about 1 fs toabout 50 μs, or from about 1 ps to about 1 ms). The fixed time periodcan comprise a time period that the primary energy source deliveryenergy to a point in the powder bed. A point can be a spot in the powderbed with an area equal to a beam fundamental length scale of the primaryenergy source. The overall time in which energy is applied to an area inthe first powder layer can be at least about 1 μs, 50 μs, 100 μs, 500μs, 1 ms, 50 ms, 0.1 second (s), 0.5 s, or 1 s. During the time that theprimary energy source delivers energy to the first powder layer, theprimary energy source can deliver energy to each point in the powderlayer once, more than once, or not at all.

At least a portion of a powder can be selectively heated by an energysource to form an intended (e.g., predetermined and/or requested) 3Dobject. The portion of the powder that did not form at least a part ofthe intended 3D object can be referred to as the remainder. In somecases, the remainder does not form a continuous structure extending over1 mm, 0.5 mm, 0.1 mm or more. The continuous structure may be acontinuous solid structure or continuous solidified structure. Acontinuous structure can be formed by transforming or partiallytransforming portions of the powder. The systems and methods describedherein may not produce a continuous solid structure in the remainder.For example, they may not produce a transformed portion of powder in theremainder. In some cases the continuous structure does not enclose the3D object or part thereof. In some cases, the remainder does not formscaffold that encloses a part of, or the entire 3D object. In somecases, the remainder does not form a lightly sintered structure thatencloses a part of, or the entire 3D object.

Energy from a second (or complementary) energy source 305 can optionallybe provided to at least a portion of the remainder of the first powderlayer. The complementary energy source 305 can be separate from theprimary energy source 304. In some cases the second energy source isintegrated with the primary energy source 304. The energy from thecomplementary energy source can be provided to the remainder of thefirst powder layer before, after, or concurrently with providing energyto the portion of the first powder layer with the primary energy source.In some cases, the primary energy source can transform the portion ofthe first powder layer. The complementary energy source can increase thetemperature of at least a portion of the remainder of the first powderlayer. In some cases the energy provided by the complementary energysource may not be sufficient to transform the remainder of the firstpowder layer. The primary energy source can be any energy sourcedisclosed herein. The primary energy source can be any energy sourcegenerating an energy beam disclosed herein. The complementary energysource can be any energy source disclosed herein. The complementaryenergy source can be any energy source generating an energy beamdisclosed herein. The complementary energy source can be a laser. Thecomplementary energy source may include a radiation comprisingelectromagnetic, electron, positron, proton, plasma, or ionic radiation.The electromagnetic beam may comprise microwave, infrared, ultravioletor visible radiation. The ion beam may include a cation or an anion. Theelectromagnetic beam may comprise a laser beam. The complementary sourcemay include a laser source. The complementary energy source may includean electron gun or any other energy source configured to providetargeted energy to a surface or base. The complementary energy sourcecan have a power per unit area that is less than the power per unit areaof the primary energy source. For example, the complementary energysource can produce and energy beam with an area that is from about 100to about 1,000,000 larger than the beam area of the first (e.g.,primary) energy source. The complementary energy source can deliverenergy to at least a portion of the remainder of the first layer ofpowder for a fixed time period. The fixed time period can be chosen suchthat a specified volume of the powder reaches a target temperature, thetime period can be chosen based on the thermal properties of the powderand the amount of energy provided by the complementary energy source.The fixed time period can be at least about 1 μs, 50 μs, 100 μs, 500 μs,1 ms, 5 ms, 10 ms, 15 ms, 20 ms, 50 ms, 100 ms, 200 ms, 500 ms, 1 s, 5s, 10 s, or 1 minute. The fixed time period can be at most about 1 μs,50 μs, 100 μs, 500 μs, 1 ms, 5 ms, 10 ms, 15 ms, 20 ms, 50 ms, 100 ms,200 ms, 500 ms, 1 s, 5 s, 10 s, or 1 minute. The fixed time period canbe any value between the above-mentioned values (e.g., from about 1 μsto about 1 minute, from about 1 μs to about 100 ms, from about 50 ms toabout 1 minute, or from about 100 ms to about 10 s). The targettemperature can be a temperature below the transforming temperature ofthe powder material. In some cases, the complementary energy can bedelivered to a single point, delivered to more than a single point, notdelivered at all, delivered at least once, twice, 5 times, 10 times, 30times, 100 times, or 1000 times to the same position or to differentposition(s) in the powder layer. Such delivery of the complementaryenergy can occur while, before, or after the powder layer is receivingenergy from the primary energy source.

In some cases, the complementary energy source can provide energy to afraction of the powder that is adjacent to at least one part of the 3Dobject. In some cases, the complementary energy source can preheat atleast a fraction of the 3D object before the at least one fraction ofthe 3D object is heated by the primary energy source. Additionally oralternatively, the complementary energy source can post-heat at least afraction of the 3D object after the 3D object is heated by the primaryenergy source. The complementary energy source can remove an oxidizedmaterial layer from at least a portion of a surface of the at least onefraction of the 3D object.

The complementary energy source can be an array, or a matrix, of laserdiodes. Each of the laser diodes in the array, or matrix, can beindependently controlled (e.g., by a control mechanism) such that thediodes can be turned off and on independently. At least a part of thelaser diodes in the array or matrix can be collectively controlled suchthat the at least a part of the laser diodes can be turned off and onsimultaneously. In some instances all the laser diodes in the array ormatrices are collectively controlled such that all of the laser diodescan be turned off and on simultaneously.

The energy per unit area or intensity of each diode laser in the matrixor array can be modulated independently (e.g., by a control mechanism orsystem). At times, the energy per unit area or intensity of at least apart of the laser diodes in the matrix or array can be modulatedcollectively (e.g., by a control mechanism). At times, the energy perunit area or intensity of all of the laser diodes in the matrix or arraycan be modulated collectively (e.g., by a control mechanism). Thecomplimentary energy source can scan along a surface of the powder bymechanical movement of the energy source, an adjustable reflectivemirror, or a polygon light scanner. The complimentary energy source canproject energy using a DLP modulator, a one-dimensional scanner, or atwo-dimensional scanner.

After energy is provided to the portion of the first powder layer by theprimary energy source and the portion of the remainder by thecomplementary energy source the energy can be removed from the powderbed by a cooling process where a cooling process may comprisetransferring heat from the powder bed 306. In some cases, heat can betransferred from the powder bed to a heat sink. Energy (e.g., heat) canbe removed from the powder bed uniformly such that the rate of energytransfer from the portion of the first powder layer heated by primaryenergy source and the portion of the remainder heated by thecomplementary energy source transfer heat to the heat sink at asubstantially similar rate, at different rates, at patterned rates, atrandom rates or any combination thereof.

One or more primary energy sources and one or more complementary energysources can be employed. For example, at least 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 30, 100, 300 or 1,000 primary energy sources and at least 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 30, 100, 300 or 1,000 complementary energysources are employed. The primary and complementary energy sources canbe independently or collectively controllable by a control mechanism(e.g., computer), as described herein. At times, at least part of theprimary and complementary energy sources can be controlled independentlyor collectively by a control mechanism (e.g., computer).

The cooling process can be optimized to reduce the time needed to coolthe powder bed. At the conclusion of the cooling process the powder bedcan have a substantially uniform temperature. A substantially uniformtemperature can be a temperature in the powder bed wherein thedifference between the average temperature between a first and secondpoint varies by at most about 20%, 15%, 10%, 8%, 6%, 4%, 2%, 1%, 0.5%,or 0.1%. The difference between the average temperature between a firstand second point varies by any percentage value between theaforementioned percentage values (e.g., from about 0.1% to about 20%,from about 0.1% to about 5%, or from about 5% to about 20%). The firstlayer can be cooled to a predetermined temperature within a fixed timeperiod. For example, the fixed cooling time period can be at most about1 μs, 50 μs, 100 μs, 500 μs, 1 ms, 5 ms, 10 ms, 15 ms, 20 ms, 50 ms, 100ms, 200 ms, 500 ms, 1 s, 5 s, 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s,80 s, 90 s, 100 s, 110 s, 120 s, 130 s, 140 s, 150 s, 160 s, 170 s, 180s, 190 s, 200 s, 210 s, 220 s, 230 s, 240 s, 250 s, 260 s, 270 s, 280 s,290 s, 300 s, 10 minutes, 15 minutes, 30 minutes, 1 hour, 3 hours, 6hours, 12 hours, or 1 day. The fixed time period can be between any ofthe aforementioned time values (e.g., from about 1 ms to about 1 day,from about 1 μs to about 300 s, from about 1 μs to about 90 s, or fromabout 1 μs to about 10 s).

After the first layer of powder has reached a sufficiently lowtemperature of at most about 15° C., 20° C., 25° C., 30° C., 35° C., 40°C., 45° C., 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 85°C., 90° C., 100° C., 200° C., 300° C., 400° C., or 500° C., the processcan repeat by providing a second layer of powder 307 adjacent to thefirst layer. In some cases the second layer of powder 307 can be cooledto a temperature below the temperature of the powder bed. The secondlayer of powder 307 can absorb heat from the powder bed to aid in thecooling of the powder bed. In some cases at least a fraction of thefirst powder layer can be removed prior to providing the second layer ofpowder adjacent to the first layer (e.g., using the powder removingmechanism and/or the powder leveling mechanism). The primary energysource can selectively provide energy to at least a portion of thesecond powder layer. The primary energy source can be configured toprovide sufficient energy to the portion of the second powder layer suchthat at least a portion of the second powder layer transforms. Thecomplementary energy source can selectively provide energy to at least aportion of the remainder of the second powder layer. The complementaryenergy source can be configured to provide energy to the remainder ofthe second powder layer such that at least a portion of the secondpowder layer undergoes a temperature increase. The temperature increasecan be one that is insufficient to transform at least one part of thesecond powder layer.

In some instances, the 3D object can be formed using only a primaryenergy source. For example, a first layer of powder can be provided at afirst temperature (T₀). T₀ can be the average temperature in the firstlayer of powder. The primary energy source can transform at least aportion of the first layer of powder to form a transformed (e.g., fused,sintered or molten) material. Powder material in the first powder layeradjacent to the transformed material can reach a temperature below thetransforming temperature of the powder. Powder material in the firstpowder layer adjacent to the transformed material can reach atemperature below the transformation (e.g., fusion, sintering ormelting) temperature of the powder. The transformed material canexperience a temperature increase such that the temperature within thetransformed material can reach a maximum temperature (T₂). The entirefirst layer of powder can be cooled to an average temperature (T₁). T₁may be the predetermined temperature. The powder layer can be cooledfrom a surface of the powder layer. In some instances T₁ may not begreater than T₀ by a factor K_(T20) times (T₂−T₀). In some instances T₁may not be greater than T₀ by at most 0.1 times (T₂−T₀). In someinstances T₁ may not be greater than T₀ by at most 0.2 times (T₂−T₀). Insome instances T₁ may not be greater than T₀ by at most 0.8 times(T₂−T₀). The cooling of the first layer can take time as delineated forcooling time period described herein. In some cases the first layer canbe cooled to a temperature such that an average individual can touch itwithout burning or harming the average individual. In some cases thefirst layer can be cooled to the sufficiently low temperature describedherein. The transformed (e.g., molten) material can harden (e.g.,solidify) during the cooling of the first layer. A second powder layercan be provided adjacent to (e.g., above) the first powder layer and theprocess of transforming at least a portion of the powder layer, and theprocess of cooling at least a portion of the powder layer (e.g., coolingthe entire powder layer, or the entire powder bed), can be repeated. Therepetition comprises providing a subsequent powder layer, melting atleast a portion of the powder layer, and cooling at least a portion ofthe powder layer can occur until a final or partial form of a 3D objectis obtained. Cooling of the layer can occur by energy transfer from alayer to a cooling member (e.g., a heat sink). Energy can be transferredfrom a layer along a direction that is oriented away from a powder layerdisposed in the powder bed. In some cases, energy can be transferred ina direction toward the surface of a heat sink. The energy can betransferred in the direction of the exposed surface of the powder bed.The energy can be transferred upwards. The energy can be transferred toa cooling member located above the powder bed, or to the side of thepowder bed. At times, at least about 20%, 30%, 40%, 50%, 60%, 70%, 70%,80%, 90%, or 95% of the energy (e.g., heat) is transferred towards thecooling member. At times, at most about 95%, 90%, 80%, 70%, 60%, 50%,40%, 30%, 30%, or 20% of the energy is transferred towards the coolingmember. Sometimes, the energy transferred towards the cooling member canhave a percentage value between any of the aforementioned percentagevalues (e.g., from about 20% to about 95%, from about 20% to about 60%,from about 50% to about 95%).

The final form of the 3D object can be retrieved soon after cooling of afinal powder layer. Soon after cooling may be at most about 1 day, 12hours, 6 hours, 3 hours, 2 hours, 1 hour, 30 minutes, 15 minutes, 5minutes, 240 s, 220 s, 200 s, 180 s, 160 s, 140 s, 120 s, 100 s, 80 s,60 s, 40 s, 20 s, 10 s, 9 s, 8 s, 7 s, 6 s, 5 s, 4 s, 3 s, 2 s, or 1 s.Soon after cooling may be between any of the aforementioned time values(e.g., from about is to about 1 day, from about is to about 1 hour, fromabout 30 minutes to about 1 day, or from about 20 s to about 240 s). Insome cases, the cooling can occur by method comprising active cooling byconvection using a cooled gas or gas mixture comprising argon, nitrogen,helium, neon, krypton, xenon, hydrogen, carbon monoxide, carbon dioxide,or oxygen.

In some cases, unused powder can surround the three-dimensional (3D)object in the powder bed. The unused powder can be substantially removedfrom the 3D object. Substantial removal may refer to powder covering atmost about 20%, 15%, 10%, 8%, 6%, 4%, 2%, 1%, 0.5%, or 0.1% of thesurface of the 3D object after removal. Substantial removal may refer toremoval of all the powder that was disposed in the powder bed andremained as powder at the end of the 3D printing process (i.e., theremainder), except for at most about 10%, 3%, 1%, 0.3%, or 0.1% of theweight of the remainder. Substantial removal may refer to removal of allthe remainder except for at most about 50%, 10%, 3%, 1%, 0.3%, or 0.1%of the weight of the printed 3D object. The unused powder can be removedto permit retrieval of the 3D object without digging through the powder.For example, the unused powder can be suctioned out of the powder bed byone or more vacuum ports built adjacent to the powder bed. After theunused powder is evacuated, the 3D object can be removed and the unusedpowder can be re-circulated to a powder reservoir for use in futurebuilds.

The 3D object can be generated on a mesh substrate. A solid platform(e.g., base or substrate) can be disposed underneath the mesh such thatthe powder stays confined in the powder bed and the mesh holes areblocked. The blocking of the mesh holes may not allow a substantialamount of powder material to flow though. The mesh can be moved (e.g.,vertically or at an angle) relative to the solid platform by pulling onone or more posts connected to either the mesh or the solid platform(e.g., at the one or more edges of the mesh or of the base) such thatthe mesh becomes unblocked. The one or more posts can be removable fromthe one or more edges by a threaded connection. The mesh substrate canbe lifted out of the powder bed with the 3D object to retrieve the 3Dobject such that the mesh becomes unblocked. Alternatively, the solidplatform can be tilted, horizontally moved such that the mesh becomesunblocked. When the mesh is unblocked, at least part of the powder flowsfrom the mesh while the 3D object remains on the mesh.

The 3D object can be built on a construct comprising a first and asecond mesh, such that at a first position the holes of the first meshare completely obstructed by the solid parts of the second mesh suchthat no powder material can flow though the two meshes at the firstposition, as both mesh holes become blocked. The first mesh, the secondmesh, or both can be controllably moved (e.g., horizontally or in anangle) to a second position. In the second position, the holes of thefirst mesh and the holes of the second mesh are at least partiallyaligned such that the powder material disposed in the powder bed is ableto flow through to a position below the two meshes, leaving the exposed3D object.

In some cases, cooling gas can be directed to the hardened material(e.g., 3D object) for cooling the hardened material during itsretrieval. The mesh can be sized such that the unused powder will siftthrough the mesh as the 3D object is exposed from the powder bed. Insome cases, the mesh can be attached to a pulley or other mechanicaldevice such that the mesh can be moved (e.g., lifted) out of the powderbed with the 3D part.

In some cases, the 3D object (i.e., 3D part) can be retrieved within atmost about 12 hours (h), 6 h, 5 h, 4 h, 3 h, 2 h, 1 h, 30 minutes (min),20 min, 10 min, 5 min, 1 min, 40 s 20 s, 10 s, 9 s, 8 s, 7 s, 6 s, 5 s,4 s, 3 s, 2 s, or 1 s after cooling of a last powder layer. The 3Dobject can be retrieved during a time period between any of theaforementioned time periods (e.g., from about 12 h to about 1 s, fromabout 12 h to about 30 min, from about 1 h to about 1 s, or from about30 min to about 40 s). The generated 3D object can require very littleor no further processing after its retrieval. Further processing maycomprise trimming, as disclosed herein. Further processing may comprisepolishing (e.g., sanding). For example, in some cases the generated 3Dobject can be retrieved and finalized without removal of transformedpowder and/or auxiliary features. The 3D object can be retrieved whenthe three-dimensional part, composed of hardened (e.g., solidified)material, is at a handling temperature that is suitable to permit theremoval of the 3D object from the powder bed without substantialdeformation. The handling temperature can be a temperature that issuitable for packaging of the 3D object. The handling temperature a canbe at most about 120° C., 100° C., 80° C., 60° C., 40° C., 30° C., 25°C., 20° C., 10° C., or 5° C. The handling temperature can be of anyvalue between the aforementioned temperature values (e.g., from about120° C. to about 20° C., from about 40° C. to about 5° C., or from about40° C. to about 10° C.).

The systems and methods disclosed herein can provide a process forgenerating a 3D object wherein the process maintains a powder bed,comprising layers of powder material, at a substantially uniformaveraged temperature. The powder bed can include a fully or partiallyformed 3D object wherein the 3D object can be formed by repetitivetransforming and subsequent cooling operations of at least a portion ofthe powder. The completely or partially formed 3D object can be fullysupported by the powder bed such that the fully or partially formedobject floats or is suspended in the powder bed. The substantiallyuniform temperature can be lower than a melting temperature of thepowder material. For example, the substantially uniform temperature canbe at most about 15° C., 25° C., 30° C., 50° C., 75° C., 100° C., 150°C., 200° C., 300° C., 400° C., 600° C., or 1000° C. The substantiallyuniform temperature can be between any of the aforementioned temperaturevalues (e.g., from about 15° C. to about 1000° C., from about 15° C. toabout 300° C., from about 200° C. to about 1000° C., or from about 100°C. to about 500° C.).

A first layer of powder can be provided at an initial time (t₀). Atleast a portion of the first powder layer can be heated or transformed.In some cases, a portion of the first powder layer is not heated ortransformed; the powdered portion of the first layer can be heateddirectly (e.g., by an energy source) or indirectly (e.g., by heattransfer from the transformed portion(s) of powder material). The powdercan have a temperature below the transformation temperature of thepowder material. In cases where the powder is heated directly, powdercan be exposed to an energy source (e.g., the complementary energysource). The energy source that heats the powder can provide energy perunit area (S₂) to the powder portion. The energy per unit area S₂ can bewithin at most about 60%, 50%, 40%, 30%, 20%, 15%, 10%, or 5% of a firstenergy per unit area (S₁).

At least a portion of the first layer of powder can be transformed withan energy beam, for example with an energy beam from the primary energysource. The maximum energy per unit area in the first powder layer canbe the first energy per unit area (S₁). In some cases, a remainder ofthe first powder is not transformed. The remainder of the first powderlayer can be supplied with energy at a third energy per unit area S₃that is less than or equal to about a factor Ks₁₃ times S₁. The factorKs can have a value of at least about 0.8, 0.9, 0.7, 0.6, 0.5, 0.4, 0.3,0.2, 0.1, 0.07, 0.05, 0.03, or 0.01. The factor Ks₁₃ can have a value ofat most about 0.01, 0.03, 0.05, 0.07, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,0.8, or 0.9. The factor Ks₃ can have any value between theafore-mentioned Ks₁₃ values. For example, Ks₁₃ can have a value of fromabout 0.01 to about 0.9, from about 0.07 to about 0.5, from about 0.3 toabout 0.8, or from about 0.05 to about 0.2. The remainder of the firstpowder layer can be supplied with energy at a third energy per unit areaS3 that is less than or equal to about 0.1 times S₁. At least a fractionof the energy used to transform the portion of the first powder layercan be removed from the first powder layer, for example using thecooling member. A time t₂ can be a later time that occurs after theinitial time t₁. A second layer can be provided adjacent to the firstlayer at the time t₂. Overall, the energy per unit area that is flowingthrough a cross section below the first layer in the time interval fromabout t₁ to t₂ can be less than about Ks₁₃ times S₁. A cross sectionbelow the first layer can be a region parallel to the first layer. Thecross section can be a planar (e.g., horizontal) cross section. In somecases the cross section can be at least about 1 μm, 5 μm, 10 μm, 100 μm,1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 50 mm, 100 mm, 200 mm, 300 mm,400 mm, or 500 mm below the first layer. The cross section can bebetween any of the aforementioned values. For example, the cross sectioncan be from about 1 μm to about 500 mm, from about 100 μm to about 50mm, from about 5 μm to about 15 mm, from about 10 mm to about 100 mm, orfrom about 50 mm to about 500 mm.

Energy transfer can occur from a first powder layer to an adjacent(e.g., second) powder layer in a time interval from t₁ to t₂. In somecases energy transfer can occur from the first powder layer in adirection that is oriented away from the second powder layer (e.g., inthe direction of the cooling member and/or in the direction above theexposed surface of the powder bed). The energy transfer from the firstpowder layer can occur at an energy per unit area S₂. The second energyper unit area S₂ can be equal to a factor Ks₁₂ times S₁. Ks₁₂ can have avalue of at least about 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5,0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, or 0.9. Ks₁₂ can have a value ofat most about 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45,0.4, 0.35, 0.3, 0.25, 0.2, 0.15, or 0.1. Ks₁₂ can have a value betweenany of the aforementioned Ks₁₂ values. For example, Ks₁₂ can have avalue from about 0.1 to about 0.9, from about 0.25 to about 0.9, fromabout 0.3 to about 0.8, from about 0.2 to about 0.6 or from about 0.15to about 0.7. In some instances, the energy transfer may occur via acooling member (e.g., heat sink). The cooling member may be locatedabove, below or to the side of the powder layer. The cooling member maycomprise an energy conductive material. The cooling member may comprisean active energy transfer or a passive energy transfer. The coolingmember may comprise a cooling liquid (e.g., aqueous or oil), cooling gasor cooling solid. The cooling member may be further connected to acooler or a thermostat. The gas or liquid comprising the cooling membermay be stationary or circulating.

During formation of a 3D object with the systems and methods providedherein, at least a portion of a powder layer can be heated by an energysource to a temperature sufficient to transform at least a portion ofthe powder layer. In some cases, the time interval for which a portionof the powder is held at the transforming temperature can be smallrelative to the total time required to form the 3D object such that thetime averaged temperature of the powder is below the transformingtemperature of the powder.

FIG. 4 is an example of a graphical time temperature history for asystem described. The graph in FIG. 4 depicts a temperature profile 401as a function of time. The temperature profile can represent thetemperature as a function of time of at least a portion of a singlepowder layer, a group of powder layers, or all of the powder layers inthe powder bed (e.g., stacked in the powder bed). At an initial time(t₀) a layer of powder material can be provided. The layer of powdermaterial can be provided in a chamber or in an enclosure. The powder canbe provided at an initial temperature T₀. The initial temperature T₀ canbe the minimum temperature of any powder layer. The initial temperatureT₀ can be the average, median or mean temperature of any powder layer.The powder layer can be exposed to an energy source that can raise atleast a portion of the powder to a temperature T₂. In some cases, T₂ canbe a temperature at or above a transforming temperature of the powdermaterial. The temperature T₂ can be the maximum temperature in a powderlayer. Energy can be removed from the powder layer, for example by acooling member (e.g., heat sink), such that the powder layer cools to atemperature T₃. The processes of providing a powder layer, heating apowder layer to temperature T₂, and cooling the powder layer to atemperature T₃ can be repeated n times, where n can be an integergreater than or equal to 1. The repetition of these processes cangenerate a collection of adjacent powder layers (e.g., stacked powderlayers) from one layer to an n^(th) layer. The repetition of theseprocesses n times can occur over a time interval from the initial timet₀ to a later time t_(n). An additional powder layer, the n+1 powderlayer, can be provided adjacent to (e.g., above) the n^(th) powderlayer. The n+1 powder layer can be provided in the chamber. The n+1powder layer can be provided at an initial temperature T₀. The initialtemperature T₀ can be the minimum temperature of any powder layer in thecollection of powder layers one (i.e., the first powder layer) to n+1.The n+1 powder layer can be exposed to the energy source that can raiseat least a portion of the powder layer number n+1 to a temperature T₂.In some cases, T₂ can be a temperature at or above a transformingtemperature of the powder material. The temperature T₂ can be themaximum temperature in a powder layer in the collection of powder layersfrom the first layer to the n+1 layer. Energy can be removed from then+1 powder layer, for example by a heat sink, such that the n+1 powderlayer cools to a temperature T₃. Removal of the energy from the n+1powder layer can end at a time t_(n+1). A time average temperature of atleast a portion of a single powder layer, a group of powder layers, orall of the powder layers in the collection (e.g., layers one throughn+1) can be considered for the time interval from t₀ to t_(n+1). Thetemperature T₂ can be the maximum temperature in the n+1 layer in thetime interval from t₀ to t_(n+1). The temperature T₀ can be the minimumtemperature of any of the layers in the time interval from t₀ tot_(n+1). The temperature T₀ can be the mean, average or mediantemperature of any of the layers in the time interval from t₀ tot_(n+1). The temperature T₁ can be the time average temperature of anypoint or group of points in at least a subset of the layers in the timeinterval from t₀ to t_(n+1). In some cases the temperature T₁ can begreater than T₀ by a factor K_(T20) times (T₂−T₀). The factor K_(T20)can have a value of at least about 0.01, 0.03, 0.05, 0.07, 0.1, 0.2,0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9. The factor K_(T20) can have avalue of at most about 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1,0.07, 0.05, 0.03, or 0.01. The factor K_(T20) can have a value betweenany of the aforementioned values. For example, K_(T20) can have a valuefrom about 0.01 to about 0.9, from about 0.1 to about 0.5, from about0.01 to about 0.2, or from about 0.1 to about 0.9. In some cases thetemperature T₁ can be greater than T₀ by no more than about 0.2 times(T₂−T₀). In some cases the temperature T₁ can be greater than T₀ by nomore than about 0.1 times (T₂−T₀). In some cases the temperature T₁ canbe greater than T₀ by no more than about 0.05 times (T₂−T₀). In somecases the temperature T₁ can be greater than T₀ by no more than about0.01 times (T₂−T₀).

In one instance, at least one layer comprising powder material can beprovided adjacent to (e.g., above) the base, the substrate or the bottomof the enclosure. An additional layer of powder can be provided adjacentto (e.g., above) the at least one layer at a time t₁. At least a portionof the additional layer can be transformed by providing energy to atleast a portion of the additional layer. At least a fraction of theprovided energy can be removed from the additional layer such that theenergy removal is completed by a time t₂. Time t₂ can be a greater(e.g., later) time than t₁. In a time interval form t₁ to t₂ a maximumtemperature in the additional layer can be a temperature (T₂). A minimumtemperature in any of the layers can be a temperature (T₀). T₂ can begreater than T₀. The highest time averaged temperature in any point inthe layers can be a temperature (T₁). In some cases the temperature T₁can be greater than T₀ by K_(T20) times (T₂−T₀).

The primary energy source and complementary energy source can provideenergy to a base and/or a powder layer with variable power per unitarea. Power per unit area can refer to amount of power delivered to anarea (e.g., energy per unit area per time). In some cases the primaryenergy source can provide energy with a first power per unit area (P₁).The complementary energy source can provide energy with a second powerper unit area (P₂). The first power per unit area (P₁) can be higherthan the second power per unit area (P₂). For example, the second powerper unit area (P₂) can have a value of at least 0.01*P₁, 0.02*P₁,0.03*P₁, 0.04*P₁, 0.05*P₁, 0.06*P₁, 0.07*P₁, 0.08*P₁, 0.09*P₁, 0.1*P₁,0.2*P₁, 0.3*P₁, 0.4*P₁, 0.5*P₁, 0.6*P₁, 0.7*P₁, 0.8*P₁, or 0.9*P₁. Thesecond power per unit area (P₂) can have a value of at most 0.01*P₁,0.02*P₁, 0.03*P₁, 0.04*P₁, 0.05*P₁, 0.06*P₁, 0.07*P₁, 0.08*P₁, 0.09*P₁,0.1*P₁, 0.2*P₁, 0.3*P₁, 0.4*P₁, 0.5*P₁, 0.6*P₁, 0.7*P₁, 0.8*P₁, or0.9*P₁. In some cases the second power per unit area (P₂) can be inbetween any of the values listed. For example, the second power per unitarea (P₂) can be from about 0.01*P₁ to about 0.9*P₁, from about 0.3*P₁to about 0.9*P₁, from about 0.01*P₁ to about 0.4*P₁, or from about0.1*P₁ to about 0.8*P₁. The first power per unit area (P₁) can beselected such that the portion of the powder layer that is providedenergy from the primary energy source is less than or equal to about 1%,5%, 10%, 20%, 30%, 40%, or 50% of the total surface area of the powderlayer.

The power per unit area can be controlled by varying any combination ofthe area over which the energy is provided, the intensity of thedelivered energy, and the time over which the energy is provided.Providing the energy over a longer period of time will cause the energyto permeate deeper into the powder bed that can result in a temperatureincrease in deeper powder layers (i.e., earlier deposited powderlayers). The power per unit area of the primary energy source (P₁) andthe complementary energy source (P₂) can be varied such that the energyper unit area (e.g., amount of energy per unit area) delivered to thepowder bed by the primary and complementary energy sources issubstantially similar. FIG. 5 depicts an example of volumes of thepowder bed 501 that can increase in temperature from the primary andcomplementary energy sources. The primary energy source can provide ahigh intensity energy beam to a relatively small area of the powder bedfor a period of time on the order of about 1 μs or less. As a result asmall volume 502 (e.g., area and depth) of the powder bed can experiencean increase in temperature sufficient to transform the portion of thepowder bed that is exposed to the primary energy source. The powderadjacent to the portion of the powder bed that is exposed to the primaryenergy source may not transform. In comparison, the complementary energysource can deliver an energy beam with a lower intensity than theprimary energy beam to a relatively larger area for a relatively longertime period. As a result, the area exposed to the complementary energybeam can experience a lower temperature increase than the area exposedto the primary energy beam. The area exposed to the complementary energybeam can experience a temperature increase to a temperature below thetransforming temperature such that the area exposed to the complementaryenergy beam does not transform. Furthermore, the area exposed to thecomplementary energy beam can experience a temperature rise deeper in tothe powder bed (e.g., over a larger volume, 503).

In some cases the primary energy source and complementary energy sourcepower per unit areas can be adjusted non-uniformly across the portion ofthe powder layer and the remainder of the powder layer respectively. Thepower per unit areas can be adjusted non-uniformly to decrease theinfluence of imperfections. For example a region with enhanced heattransfer, for example an edge of the powder bed can lose heat morequickly than an area of the powder bed towards the center. In order tocompensate for such imperfection the primary and/or complementary energysource can provide a slightly higher power per unit area to the edges ascompared to the center of the powder bed. The temperature of the powderbed can be monitored continuously using at least one temperature sensorand the power per unit area of the primary and/or complementary energysource can be modulated in real time to correct temperature gradientsand/or non-uniformities.

The primary and complementary energy sources can heat the powder layerat substantially the same time. FIG. 6 depicts an example of a timelinethat can be implemented to form a layer of the 3D object. Starting at aninitial time t₀ the primary energy source and the complementary energysource can begin heating the powder bed. The primary energy source canheat the powder surface for a finite period of time (e.g., for a fewmicro seconds 601). After the primary energy source finished heating thepowder bed it may turn off. Concurrently the complementary energy sourcecan heat the remainder of the first layer and/or a lateral portion ofthe base 602. The complementary energy source can heat the remainder ofthe first layer and/or a lateral portion of the base for a second timeperiod (e.g., time period of 10-60 milliseconds). Once both the primaryand complementary energy sources have finished heating the powder bedthe powder bed can be cooled 603. Formation of one layer includingheating and cooling of the powder layer can take up to about 30 seconds.The portion of the powder bed heated by the primary energy source andthe portion of the powder bed heated by the complementary energy sourcecan be cooled at substantially the same rate. Cooling both portions ofthe powder bed at the same rate can reduce thermal stresses such thatthe three-dimensional part formed by transforming (e.g., melting) andcooling the portion of the powder bed does not move or deform (e.g.,warp) during the cooling process. Cooling both portions of the powderbed at substantially the same rate can reduce or eliminate the need forauxiliary support features to hold the 3D object in place during theprinting process. The energy beam of the primary and/or complementarybeam can have a variable intensity and/or a variable spot size and spotgeometries.

At least a portion of the powder layer (e.g., first powder layer) can beheated by the primary energy source. The portion of the powder layer canbe heated to a temperature that is greater than or equal to atemperature wherein at least part of the powder material is transformedto a liquid state (referred to herein as the liquefying temperature) ata given pressure. The liquefying temperature can be equal to a liquidustemperature where the entire material is at a liquid state at a givenpressure. The liquefying temperature of the powder material can be thetemperature at or above which at least part of the powder materialtransitions from a solid to a liquid phase at a given pressure. Theremainder of the powder layer can be heated by the complementary energysource. The remainder of the powder layer can be at a temperature thatis less than the liquefying temperature. The maximum temperature of thetransformed portion of the powder and the temperature of the remainderof the powder can be different. The solidus temperature of the powdermaterial can be a temperature wherein the powder material is in a solidstate at a given pressure. After the portion of the first layer isheated to the temperature that is greater than or equal to a liquefyingtemperature of the powder material by the primary energy source, theportion of the first layer is cooled to allow the transformed powderportion to harden (e.g., solidify). Once the portion of the first layerhardens, a subsequent (e.g., second) powder layer can be providedadjacent to (e.g., above) the first powder layer. The portion of thefirst layer can harden during cooling of both the transformed portion,and the remaining powder of the first layer in the powder bed. In somecases, the liquefying temperature can be at least about 100° C., 200°C., 300° C., 400° C., or 500° C., and the solidus temperature can be atmost 500° C., 400° C., 300° C., 200° C., or 100° C. For example, theliquefying temperature is at least about 300° C. and the solidustemperature is at most about 300° C. As another example, the liquefyingtemperature is at least about 400° C. and the solidus temperature is atmost about 400° C. The liquefying temperature may be different than thesolidus temperature. In some instances, the temperature of the powdermaterial is maintained above the solidus temperature of the material andbelow its liquefying temperature. In some instances, the material fromwhich the powder material is composed has a super cooling temperature(or super cooling temperature regime). As the energy source heats up thepowder material to cause at least part of the powder material to melt,the melted material will remain melted as the powder bed is held at orabove the material super cooling temperature of the material, but belowits melting point. When two or more materials make up the powder bed ata specific ratio, the materials may form a eutectic material ontransforming (e.g., fusion, sintering, melting, bonding, or connecting)the powder material. The liquefying temperature of the formed eutecticmaterial may be the temperature at the eutectic point, close to theeutectic point, or far from the eutectic point. Close to the eutecticpoint may designate a temperature that is different from the eutectictemperature (i.e., temperature at the eutectic point) by at most about0.1° C., 0.5° C., 1° C., 2° C., 4° C., 5° C., 6° C., 8° C., 10° C., or15° C. A temperature that is farther from the eutectic point than thetemperature close to the eutectic point is designated herein as atemperature far from the eutectic point. The process of transforming(e.g., liquefying) and hardening (e.g., solidifying) a portion of thefirst layer can be repeated until all layers of a 3D object are formed.At the completion of the formation process, the generated 3D object canbe removed from the powder bed. The remaining powder can be separatedfrom the portion at the completion of the process. The 3D object can besolidified and removed from the container accommodating the powder bed.

A 3D object can be formed from a powder bed. The powder can compriseparticles of a material that is the desired composition material of the3D object. The powder bed can comprise a mixture of materials that upontransforming will comprise the material that is the desired compositionmaterial of the 3D object. A layer of powder material can be providedadjacent to a base (or to a substrate, bottom of the enclosure, orbottom of the container accommodating the powder bed) or to anotherlayer of the powder material. The powder can be confined in a container(referred to herein as “powder bed”). In some cases the powder bed canbe insulated, actively cooled, actively heated, or held at a constanttemperature using a temperature-adjusting unit (e.g., a heater or arefrigerator). At least part of the temperature-adjusting unit may beembedded in the walls of the powder bed. The 3D object can be formed bysequential addition of material layers in a predetermined pattern. Afirst layer can be formed by transforming a portion of a first powderlayer without transforming a remainder of the first powder layer. Attimes, the first deposited powder layer remains untransformed, andtransformation occurs in subsequently deposited powder layers. A primaryenergy source can propagate (e.g., scan) along the surface of at least aportion of the first powder layer in a predetermined pattern. Theportion of the first powder layer that interacts with (e.g., scanned by)the primary energy source can experience a temperature increase. Thetemperature increase can transform the material to create a transformedmaterial that subsequently hardens (e.g., solidifies) from at least aportion of the powder layer (e.g., the first powder layer). The scanrate of the primary energy source can be at least about 0.01 mm/s, 0.1mm/s, 1 mm/s, 5 mm/s, 10 mm/s, 15 mm/s, 20 mm/s, 25 mm/s, or 50 mm/s.The scan rate of the primary energy source can be at most about 0.01mm/s, 0.1 mm/s, 1 mm/s, 5 mm/s, 10 mm/s, 15 mm/s, 20 mm/s, 25 mm/s, or50 mm/s. The scan rate of the primary energy source can be any value inbetween the above-mentioned values (e.g., from about 0.01 mm/s to about50 mm/s, from about 0.01 mm/s to about 20 mm/s, or from about 15 mm/s toabout 50 mm/s).

A complementary energy source can provide energy to heat up a remainderof the first powder layer. The remainder can be an area on the surfaceof the first powder layer that is adjacent to the portion of the firstpowder layer that is scanned by the primary energy source. The remaindercan be heated to a temperature below the transforming temperature suchthat the remaining powder does not transform (e.g., melt). The remainingpowder can remain in a solid state throughout the formation of the 3Dobject. The microstructure and/or grain structure of the remainingpowder can remain substantially unaltered throughout the formation ofthe 3D object, as compared with the deposited powder material.Substantially unaltered refers to the lack of phase change, and to achange of grain size or microstructure size of at most about 20%, 10%,5%, 1% or less.

After providing the primary and complementary energy source to theportion of the first powder layer and the remainder of the first powderlayer, respectively, the first powder layer can be cooled. Thetransformed portion of the first powder layers can harden (e.g.,solidify) while the first powder layer is cooled. The portion and theremaining powder can be cooled at substantially the same rate. After thepowder layer is cooled, a subsequent (e.g., second) powder layer can beprovided adjacent to (e.g., above) the first powder layer and theprocess can be repeated until all layers (e.g., cross sections) of the3D object are formed such that the complete 3D object is generated. FIG.7 summarizes a printing process as described herein. A first powderlayer can be irradiated by a primary energy source 701. The first layercan be irradiated by a complementary energy source 702; the irradiationby the complementary energy source can be before, after, or concurrentwith the irradiation by the primary energy source. In some cases thecomplementary energy source is not used to irradiate the first layer orsubsequent layers. The first powder layer can then be cooled 703. Thefirst powder layer can be cooled uniformly such that temperaturegradients are mild or substantially not present in the powder bed. Insome cases portions of the powder bed that were transformed by theprimary energy source can solidify during the cooling operation 703.After the cooling, a subsequent (e.g., second) layer of powder can beprovided adjacent to the first layer 704. The process can repeat withirradiation of the subsequent layer of powder until the 3D object isformed.

The 3D object can be formed without one or more auxiliary featuresand/or without contacting a base. The one or more auxiliary features(which may include a base support) can be used to hold or restrain the3D object during formation. In some cases auxiliary features can be usedto anchor or hold a 3D object or a portion of a 3D object in a powderbed. The one or more auxiliary features can be specific to a part andcan increase the time needed to form the 3D object. The one or moreauxiliary features can be removed prior to use or distribution of the 3Dobject. The longest dimension of a cross-section of an auxiliary featurecan be at most about 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600nm, 700 nm, 800 nm, 900 nm, or 1000 nm, 1 μm, 3 μm, 10 μm, 20 μm, 30 μm,100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 700 μm, 1 mm, 3 mm, 5 mm, 10 mm,20 mm, 30 mm, 50 mm, 100 mm, or 300 mm. The longest dimension of across-section of an auxiliary feature can be at least about 50 nm, 100nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or1000 nm, 1 μm, 3 μm, 10 μm, 20 μm, 30 μm, 100 μm, 200 μm, 300 μm, 400μm, 500 μm, 700 μm, 1 mm, 3 mm, 5 mm, 10 mm, 20 mm, 30 mm, 50 mm, 100mm, or 300 mm. The longest dimension of a cross-section of an auxiliaryfeature can be any value between the above-mentioned values (e.g., fromabout 50 μm to about 300 mm, from about 5 μm to about 10 mm, from about50 μm to about 10 mm, or from about 5 mm to about 300 mm).

Without wishing to be bound to theory, the cooling rate of the powderbed that surrounds the solidifying part, may affect the thermal stresseswithin that solidifying part. In the methods and systems providedherein, the powder bed is cooled at substantially the same rate suchthat the temperature gradients in the powder bed are substantially flat.The flat temperature gradients provided by the systems and methodsherein may at least reduce (e.g., eliminate) thermal stresses on thesolidifying part, and thus at least may reduce thermal stresses in theformed 3D object. As a result of the reduction of thermal stresses onthe 3D object during formation, the 3D object may be formed withoutauxiliary features. Eliminating the need for auxiliary features candecrease the time and cost associated with generating thethree-dimensional part. In some examples, the 3D object may be formedwith auxiliary features. In some examples, the 3D object may be formedwith contact to the container accommodating the powder bed.

The methods and systems provided herein can result in fast and efficientformation of 3D objects. In some cases, the 3D object can be transportedwithin at most about 120 min, 100 min, 80 min, 60 min, 40 min, 30 min,20 min, 10 min, or 5 min after the last layer of the object hardens(e.g., solidifies). In some cases, the 3D object can be transportedwithin at least about 120 min, 100 min, 80 min, 60 min, 40 min, 30 min,20 min, 10 min, or 5 min after the last layer of the object hardens. Insome cases, the 3D object can be transported within any time between theabove-mentioned values (e.g., from about 5 min to about 120 min, fromabout 5 min to about 60 min, or from about 60 min to about 120 min). The3D object can be transported once it cools to a temperature of at mostabout 100° C., 90° C., 80° C., 70° C., 60° C., 50° C., 40° C., 30° C.,25° C., 20° C., 15° C., 10° C., or 5° C. The 3D object can betransported once it cools to a temperature value between theabove-mentioned temperature values (e.g., from about 5° C. to about 100°C., from about 5° C. to about 40° C., or from about 15° C. to about 40°C. Transporting the 3D object can comprise packaging and/or labeling the3D object. In some cases the 3D object can be transported directly to aconsumer, government, organization, company, hospital, medicalpractitioner, engineer, retailer, or any other entity, or individualthat is interested in receiving the object.

The system can comprise a controlling mechanism (e.g., a controller)comprising a computer processing unit (e.g., a computer) coupled to theprimary (first) and optionally to a complementary (e.g., second) energysources. The computer can be operatively coupled to the primary andoptionally to the complementary energy sources through a wired orthrough a wireless connection. In some cases, the computer can be onboard a user device. A user device can be a laptop computer, desktopcomputer, tablet, smartphone, or another computing device. Thecontroller can be in communication with a cloud computer system or aserver. The controller can be programmed to selectively direct a firstenergy source to apply energy to the portion of the layer of powder at apower per unit area (P₁). The controller can be in communication withthe scanner configured to articulate the first energy source to applyenergy to the portion of the layer of powder at a power per unit area(P₁). The controller can be further programmed to selectively direct(e.g., articulate to) the second energy source to apply energy to atleast a portion of the remainder of the layer and/or the lateral portionof the base at a second power per unit area (P₂). The controller can beoperatively connected to the scanner configured to articulate the firstenergy source to apply energy to the portion of the layer of powder at apower per unit area (P₂). The controller (e.g., computer) can beprogrammed to direct the first energy source and second energy source toapply energy substantially simultaneously.

In some cases, the system can comprise a controller (e.g., computer)coupled to an energy source. The controller can be programmed totransform or heat a portion of a powder layer with the energy sourcesuch that the portion reaches a maximum temperature T₂. The temperatureT₂ can be higher than an initial temperature of the powder layer T₀. Thecontroller can be further configured to facilitate the cooling of thepowder layer to an average temperature T₁ in a time period that is atmost about 1 day, 12 hours, 6 hours, 3 hours, 2 hours, 1 hour, 30minutes, 15 minutes, 5 minutes, 240 seconds (s), 220 s, 200 s, 180 s,160 s, 140 s, 120 s, 100 s, 80 s, 60 s, 40 s, 20 s, 10 s, 9 s, 8 s, 7 s,6 s, 5 s, 4 s, 3 s, 2 s, or 1 s, to form a hardened material that is atleast a portion of the 3D object. In some cases T₁ is not greater thanT₀ than about 0.2 times (T₂-T₁). In some instances T₁ may not be greaterthan T₀ by at most about 0.1 times (T₂-T₀). In some instances T₁ may notbe greater than T₀ by at most about 0.2 times (T₂-T₀). In some instancesT₁ may not be greater than T₀ by at most about K_(T20) times (T₂-T₀).

The scanner can be included in an optical system that is configured todirect energy from the first energy source to a predetermined positionof the powder layer. The controller can be programmed to control atrajectory of the first and/or the second energy source with the aid ofthe optical system. The control system can regulate a supply of energyfrom the energy source to a powder layer to form a 3D object or aportion thereof.

The controller (e.g., computer having one or more computer processors)can be in network communication with a remote computer system thatsupplies instructions to the computer system to generate the 3D object.The controller can be in network communication with the remote computerthrough a wired or through a wireless connection. The remote computercan be a laptop, desktop, smartphone, tablet, or other computer device.The remote computer can comprise a user interface through which a usercan input design instructions and parameters for the 3D object. Theinstructions can be a set of values or parameters that describe theshape and dimensions of the 3D object. The instructions can be providedthrough a file having a Standard Tessellation Language file format. Inan example, the instructions can come from a 3D modeling program (e.g.,AutoCAD, SolidWorks, Google SketchUp, or SolidEdge). In some cases, themodel can be generated from a provided sketch, image, or 3D object. Theremote computer system can supply design instruction to the computerprocessor. The controller can direct the first and the optionally secondenergy source in response to the instructions received from the remotecomputer. The controller can be further programmed to optimize atrajectory of path (e.g., vector) of the energy applied from the firstand/or second energy source to a portion or remainder of the powderlayer, respectively. Optimizing the trajectory of energy application cancomprise minimizing time needed to heat the powder, minimizing timeneeded to cool the powder, minimizing the time needed to scan the areathat needs to receive energy or minimizing the energy emitted by theenergy source(s).

In some cases, the controller can be programmed to calculate thenecessary first power per unit area (P₁) and second power per unit area(P₂) that should be provided to the powder layer in order to achieve thedesired result. The controller can be programmed to determine the timethat an energy source should be incident on an area of a determined sizein order to provide the necessary first or second powder density. Insome cases the desired result can be to provide uniform energy per unitarea within the powder bed. Additionally the desired result can be totransform a portion of the layer of the powder bed with the primaryenergy source at the first power per unit area (P₁) and to not transformthe remainder of the layer with the complementary energy source at thesecond power per unit area (P₂). The controller can be programmed tooptimize the application of energy from the first and/or second energysources. Optimizing the energy application can comprises minimizing timeneeded to heat the powder, minimizing time needed to cool the powder,minimizing the energy emitted by the energy source(s), or anycombination thereof.

The system can further comprise a cooling member (e.g., heat sink)configured to cool, heat or stabilize the temperature of the portion ofthe transformed powder layer and/or at least a portion of the remainderof the powder layer. The cooling member can be configured to cool, heator stabilize (e.g., equilibrate) the temperature of the portion of thepowder layer and the at least a portion of the remainder of the powderlayer at substantially the same rate. The cooling member can cool, heator stabilize the temperature of the portion of the powder layer and/orat least a portion of the remainder of the powder layer by initiatingheat transfer from the powder to the cooling member. For example, thecooling member can be configured to remove energy at a rate greater thanor equal to about P₁. The cooling member can be maintained at atemperature that is substantially lower than the temperature of thepowder bed. Heat can be transferred from the powder material to thecooling member by any one or combination of heat transfer modesincluding conduction, natural convection, forced convection, orradiation. The cooling member may comprise a material that conducts heatefficiently. For example, the cooling member may comprise liquid (e.g.,water). The liquid may circulate in the cooling member within channelsin or on the cooling member. The heat (thermal) conductivity of thecooling member may be at least about 20 Watts per meters times degreesKelvin (W/mK), 50 W/mK, 100 W/mK, 150 W/mK, 200 W/mK, 205 W/mK, 300W/mK, 350 W/mK, 400 W/mK, 450 W/mK, 500 W/mK, 550 W/mK, 600 W/mK, 700W/mK, 800 W/mK, 900 W/mK, or 1000 W/mK. The thermal conductivity of thecooling member may be any value between the aforementioned thermalconductivity values (e.g., from about 20 W/mK to about 1000 W/mK, fromabout 20 W/mK to about 500 W/mK, or from about 500 W/mK to about 1000W/mK). The aforementioned thermal conductivity can be at a temperatureof equal to or above about 100° C., 200° C., 300° C., 400° C., 500° C.,or 800° C. The cooling member can be separated from the powder bed orpowder layer by a gap. The gap can have a variable or adjustablespacing. Alternatively, the cooling member can contact the powder bed orthe powder layer. In some instances, the cooling member can bealternately and sequentially brought in contact with the powder layer.The gap can be filled with a gas. The gas can be chosen in order toachieve a specific heat transfer property between the powder and thecooling member. For example, a gas with high thermal conductivity can bechosen to increase the rate of conductive heat transfer from the powderto the plate. The gas between the plate and the powder layer cancomprise argon, nitrogen, helium, neon, krypton, xenon, hydrogen, carbonmonoxide, carbon dioxide, or oxygen. The gas can be air. The gas can byany gas mentioned herein. In some cases the system can be stored andoperated in a vacuum chamber in which case there will be at most a thinlayer (e.g., as compared to ambient atmosphere) between the plate andthe powder layer. The distance between the cooling member and the powderlayer can influence the heat transfer between the cooling member and thepowder layer. The vertical distance of the gap from the exposed surfaceof the powder bed may be at least about 50 μm, 100 μm, 250 μm, 0.5 mm, 1mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 20 mm, 30 mm,40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm. The verticaldistance of the gap from the exposed surface of the powder bed may be atmost about 50 μm, 100 μm, 250 μm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm,6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm,80 mm, 90 mm, or 100 mm. The vertical distance of the gap from theexposed surface of the powder bed may be any value between theaforementioned values (e.g., from about 50 μm to about 100 mm, fromabout 50 μm to about 60 mm, or from about 40 mm to about 100 mm). Insome instances, there is no gap (i.e., the gap is zero). In some cases,the gap can be adjustable. The cross section of the gap can becontrolled by a control system (e.g., a computer). The gap can have asubstantially uniform dimension across the entire cooling member, oracross the powder bed. In some cases, the gap distance can vary acrossthe powder bed. In some instances, the gap can be adjusted such that theplate is in contact with the powder bed (e.g., the exposed surface ofthe powder bed). A mechanism can be used to flexibly move the coolingmember in and out of contact with the powder bed. The mechanism can beelectronically or manually controlled (e.g., by the controller). In anexample, the mechanism can be an array of curved leaf springs, flexibleneedle springs, a set of rolling cylinders. The contact pressure betweenthe cooling member (e.g., plate) and the powder bed can beelectronically or manually adjusted.

In some cases, a gas bearing assisted cooling process can be utilized toincrease the cooling rate of the powder. In this embodiment a planar airbearing can be creating using a set of openings in the cooling platefacing the powder bed. Pressurized gas can be injected from one set ofopenings to the gap and can leave the gap through a second set ofopenings. The gas bearing can induce forced convection and thereforeincrease the heat transfer rate of heat from the powder bed. In anotherexample, thermo-acoustic heat extraction can be used to increase thecooling rate of the powder bed.

The cooling member can further comprise one or more holes or openings.In some cases at least as about 5%, 10%, 20%, 30%, 40%, 50%, 60% or 70%of the surface area of the cooling member can be an opening or hole. Theholes or openings can be configured to allow the first and the optionalsecond energy sources to access the powder layer. In some cases, thecooling member can be substantially transparent. The cooling member canbe adapted to be selectively positioned between the powder bed (or thecontainer accommodating the powder bed) and the first and optionallysecond energy sources. In some cases a scanner can translate the coolingmember such that the hole(s) remains in a location such that the firstand optionally second energy sources can access the powder layer as theyare scanned across the powder layer. The scanner that controls movementof the plate can be synchronized with the at least one scanner thatpermit articulation of the first and second energy sources. The coolingmember can controllably track energy applied to the portion of thepowder layer from the first energy source. Movement of the coolingmember can be controlled by the control mechanism (e.g., controller).The controller (e.g., computer) can be programmed to control movement ofthe cooling member. In some cases, the controller can be programmed tooptimize the removal of energy from the portion and or remainder of thepowder layer. Optimizing removal of energy from the portion and orremainder of the powder layer can include changing the gap length orwidth, moving the cooling member, initiating a forced convection system(e.g., fan), adjusting gas composition, or any other process that caninfluence time or efficiency variables. The controller can be furtherprogrammed to control (e.g., regulate) a temperature profile of the baseseparate from a temperature profile of the powder layer. The controller(e.g., computer) can additionally be programmed to ensure that regionsof the powder bed surface are covered by solid portions and open (hole)portions of the cooling member for equal durations of time to maintainuniform heat transfer. If it is not possible to maintain uniform heattransfer by movement of the plate, the complementary heat source canprovide more or less energy to area that will receive more or less timeunder the cooling member respectively.

One or more of the system components can be contained in the enclosure(e.g., chamber). The enclosure can include a reaction space that issuitable for introducing precursor to form a 3D object, such as powdermaterial. The enclosure can contain the base. In some cases theenclosure can be a vacuum chamber, a positive pressure chamber, or anambient pressure chamber. The enclosure can comprise a gaseousenvironment with a controlled pressure, temperature, and/or gascomposition. The gas composition in the environment contained by theenclosure can comprise a substantially oxygen free environment. Forexample, the gas composition can contain at most at most about 100,000parts per million (ppm), 10,000 ppm, 1000 ppm, 500 ppm, 400 ppm, 200ppm, 100 ppm, 50 ppm, 10 ppm, 5 ppm, 1 ppm, 100,000 parts per billion(ppb), 10,000 ppb, 1000 ppb, 500 ppb, 400 ppb, 200 ppb, 100 ppb, 50 ppb,10 ppb, 5 ppb, 1 ppb, 100,000 parts per trillion (ppt), 10,000 ppt, 1000ppt, 500 ppt, 400 ppt, 200 ppt, 100 ppt, 50 ppt, 10 ppt, 5 ppt, or 1 pptoxygen. The gas composition in the environment contained within theenclosure can comprise a substantially moisture (e.g., water) freeenvironment. The gaseous environment can comprise at most about 100,000ppm, 10,000 ppm, 1000 ppm, 500 ppm, 400 ppm, 200 ppm, 100 ppm, 50 ppm,10 ppm, 5 ppm, 1 ppm, 100,000 ppb, 10,000 ppb, 1000 ppb, 500 ppb, 400ppb, 200 ppb, 100 ppb, 50 ppb, 10 ppb, 5 ppb, 1 ppb, 100,000 ppt, 10,000ppt, 1000 ppt, 500 ppt, 400 ppt, 200 ppt, 100 ppt, 50 ppt, 10 ppt, 5ppt, or 1 ppt water. The gaseous environment can comprise a gas selectedfrom the group consisting of argon, nitrogen, helium, neon, krypton,xenon, hydrogen, carbon monoxide, carbon dioxide, and oxygen. Thegaseous environment can comprise air. The chamber pressure can be atleast about 10⁻⁷ Torr, 10⁻⁶ Torr, 10⁻⁵ Torr, 10⁻⁴ Torr, 10⁻³ Torr, 10⁻²Torr, 10⁻¹ Torr, 1 Torr, 10 Torr, 100 Torr, 1 bar, 760 Torr, 1000 Torr,1100 Torr, 2 bar, 3 bar, 4 bar, 5 bar, or 10 bar. The chamber pressurecan be of any value between the afore-mentioned chamber pressure values(e.g., from about 10⁻⁷ Torr to about 10 bar, from about 10⁻⁷ Torr toabout 1 bar, or from about 1 bar to about 10 bar). In some cases theenclosure pressure can be standard atmospheric pressure.

The enclosure can be maintained under vacuum or under an inert, dry,non-reactive and/or oxygen reduced (or otherwise controlled) atmosphere(e.g., a nitrogen (N₂), helium (He), or argon (Ar) atmosphere). In someexamples, the enclosure is under vacuum, such as at a pressure that isat most about 1 Torr, 10⁻³ Torr, 10⁻⁶ Torr, or 10⁻⁸ Torr. The atmospherecan be provided by providing an inert, dry, non-reactive and/or oxygenreduced gas (e.g., Ar) in and/or flowing the gas through the chamber.

In some examples, a pressure system is in fluid communication with theenclosure. The pressure system can be configured to regulate thepressure in the enclosure. In some examples, the pressure systemincludes one or more vacuum pumps selected from mechanical pumps, rotaryvain pumps, turbomolecular pumps, ion pumps, cryopumps and diffusionpumps. The one or more vacuum pumps may comprise Rotary vane pump,diaphragm pump, liquid ring pump, piston pump, scroll pump, screw pump,Wankel pump, external vane pump, roots blower, multistage Roots pump,Toepler pump, or Lobe pump. The one or more vacuum pumps may comprisemomentum transfer pump, regenerative pump, entrapment pump, Venturivacuum pump, or team ejector. The pressure system can include valves,such as throttle valves. The pressure system can include a pressuresensor for measuring the pressure of the chamber and relaying thepressure to the controller, which can regulate the pressure with the aidof one or more vacuum pumps of the pressure system. The pressure sensorcan be coupled to a control system. The pressure can be electronicallyor manually controlled.

In some examples, the pressure system includes one or more pumps. Theone or more pumps may comprise a positive displacement pump. Thepositive displacement pump may comprise rotary-type positivedisplacement pump, reciprocating-type positive displacement pump, orlinear-type positive displacement pump. The positive displacement pumpmay comprise rotary lobe pump, progressive cavity pump, rotary gearpump, piston pump, diaphragm pump, screw pump, gear pump, hydraulicpump, rotary vane pump, regenerative (peripheral) pump, peristalticpump, rope pump, or flexible impeller. Rotary positive displacement pumpmay comprise gear pump, screw pump, or rotary vane pump. Thereciprocating pump comprises plunger pump, diaphragm pump, piston pumpsdisplacement pumps, or radial piston pump. The pump may comprise avalveless pump, steam pump, gravity pump, eductor-jet pump, mixed-flowpump, bellow pump, axial-flow pumps, radial-flow pump, velocity pump,hydraulic ram pump, impulse pump, rope pump, compressed-air-powereddouble-diaphragm pump, triplex-style plunger pump, plunger pump,peristaltic pump, roots-type pumps, progressing cavity pump, screw pump,or gear pump.

Systems and methods presented herein can facilitate formation of customor stock 3D objects for a customer. A customer can be an individual, acorporation, an organization, a government organization, a non-profitorganization, or another organization or entity. A customer can submit arequest for formation of a 3D object. The customer can provide an itemof value in exchange for the 3D object. The customer can provide adesign for the 3D object. The customer can provide the design in theform of a stereo lithography (STL) file. Alternatively, the customer canprovide a design where the design can be a definition of the shape anddimensions of the 3D object in any other numerical or physical form. Insome cases, the customer can provide a three-dimensional model, sketch,or image as a design of an object to be generated. The design can betransformed in to instructions usable by the printing system toadditively generate the 3D object. The customer can further provide arequest to form the 3D object from a specific material or group ofmaterials. For example the customer can specify that the 3D objectshould be made from one or more than one of the materials used for 3Dprinting described herein. The customer can request a specific materialwithin that group of material (e.g., a specific elemental metal, aspecific alloy, a specific ceramic or a specific allotrope of elementalcarbon). In some cases, the design does not contain auxiliary features.

In response to the customer request the 3D object can be formed orgenerated with the printing system as described herein. In some cases,the 3D object can be formed by an additive 3D printing process.Additively generating the 3D object can comprise successively depositingand melting a powder comprising one or more materials as specified bythe customer. The 3D object can subsequently be delivered to thecustomer. The 3D object can be formed without generation or removal ofauxiliary features. Auxiliary features can be support features thatprevent a 3D object from shifting, deforming or moving during formation.The apparatuses, system and methods provided herein can eliminate theneed for auxiliary features. In some cases, the 3D object can beadditively generated in a period of at most about 7 days, 6 days, 5days, 3 days, 2 days, 1 day, 12 hours, 6 hours, 5 hours, 4 hours, 3hours, 2 hours, 1 hour, 30 min, 20 min, 10 min, 5 min, 1 min, 30seconds, or 10 seconds. In some cases, the 3D object can be additivelygenerated in a period between any of the aforementioned time periods(e.g., from about 10 seconds to about 7 days, from about 10 seconds toabout 12 hours, from about 12 hours to about 7 days, or from about 12hours to about 10 minutes).

The 3D object (e.g., solidified material) that is generated for thecustomer can have an average deviation value from the intendeddimensions of at most about 0.5 microns (μm), 1 μm, 3 μm, 10 μm, 30 μm,100 μm, 300 μm or less. The deviation can be any value between theaforementioned values. The average deviation can be from about 0.5 μm toabout 300 μm, from about 10 μm to about 50 μm, from about 15 μm to about85 μm, from about 5 μm to about 45 μm, or from about 15 μm to about 35μm. The 3D object can have a deviation from the intended dimensions in aspecific direction, according to the formula Dv+L/K_(dv), wherein Dv isa deviation value, L is the length of the 3D object in a specificdirection, and K_(dv) is a constant. Dv can have a value of at mostabout 300 μm, 200 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 5 μm, 1μm, or 0.5 μm. Dv can have a value of at least about 0.5 μm, 1 μm, 3 μm,5 μm, 10 μm, 20 μm, 30 μm, 50 μm, 70 μm, 100 μm, 300 μm or less. Dv canhave any value between the aforementioned values. Dv can have a valuethat is from about 0.5 μm to about 300 μm, from about 10 μm to about 50μm, from about 15 μm to about 85 μm, from about 5 μm to about 45 μm, orfrom about 15 μm to about 35 μm. K_(dv) can have a value of at mostabout 3000, 2500, 2000, 1500, 1000, or 500. K_(dv) can have a value ofat least about 500, 1000, 1500, 2000, 2500, or 3000. K_(dv) can have anyvalue between the aforementioned values. K_(dv) can have a value that isfrom about 3000 to about 500, from about 1000 to about 2500, from about500 to about 2000, from about 1000 to about 3000, or from about 1000 toabout 2500.

The intended dimensions can be derived from a model design. The 3D partcan have the stated accuracy value immediately after formation withoutadditional processing or manipulation. Receiving the order for theobject, formation of the object, and delivery of the object to thecustomer can take at most about 7 days, 6 days, 5 days, 3 days, 2 days,1 day, 12 hours, 6 hours, 5 hours, 4 hours, 3 hours, 2 hours, 1 hour, 30min, 20 min, 10 min, 5 min, 1 min, 30 seconds, or 10 seconds. In somecases, the 3D object can be additively generated in a period between anyof the aforementioned time periods (e.g., from about 10 seconds to about7 days, from about 10 seconds to about 12 hours, from about 12 hours toabout 7 days, or from about 12 hours to about 10 minutes). The time canvary based on the physical characteristics of the object, including thesize and/or complexity of the object. The generation of the 3D objectcan be performed without iterative and/or without corrective printing.The 3D object may be devoid of auxiliary supports or an auxiliarysupport mark (e.g., that is indicative of a presence or removal of theauxiliary support feature).

The present disclosure also provides controllers or control mechanisms(e.g., comprising a computer system) that are programmed to implementmethods of the disclosure. FIG. 8 schematically depicts a computersystem 801 that is programmed or otherwise configured to facilitate theformation of a 3D object according to the methods provided herein. Thecomputer system 801 can regulate various features of printing methodsand systems of the present disclosure, such as, for example, regulatingheating, cooling and/or maintaining the temperature of a powder bed,process parameters (e.g., chamber pressure), the scanning route of theenergy source, and/or the application of the amount of energy emitted toa selected location of a powder bed by the energy source. The computersystem 801 can be part of or be in communication with a printing systemor apparatus, such as a 3D printing system or apparatus of the presentdisclosure. The computer may be coupled to one or more sensors connectedto various parts of the 3D printing system or apparatus.

The computer system 801 can include a central processing unit (CPU, also“processor,” “computer” and “computer processor” used herein) 805, whichcan be a single core or multi core processor, or a plurality ofprocessors for parallel processing. Alternatively or in addition to, thecomputer system 801 can include a circuit, such as anapplication-specific integrated circuit (ASIC). The computer system 801also includes memory or memory location 810 (e.g., random-access memory,read-only memory, flash memory), electronic storage unit 815 (e.g., harddisk), communication interface 820 (e.g., network adapter) forcommunicating with one or more other systems, and peripheral devices825, such as cache, other memory, data storage and/or electronic displayadapters. The memory 810, storage unit 815, interface 820 and peripheraldevices 825 are in communication with the CPU 805 through acommunication bus (solid lines), such as a motherboard. The storage unit815 can be a data storage unit (or data repository) for storing data.The computer system 801 can be operatively coupled to a computer network(“network”) 830 with the aid of the communication interface 820. Thenetwork 830 can be the Internet, an Internet and/or extranet, or anintranet and/or extranet that is in communication with the Internet. Thenetwork 830 in some cases is a telecommunication and/or data network.The network 830 can include one or more computer servers, which canenable distributed computing, such as cloud computing. The network 830,in some cases with the aid of the computer system 801, can implement apeer-to-peer network, which may enable devices coupled to the computersystem 801 to behave as a client or a server.

The CPU 805 can execute a sequence of machine-readable instructions,which can be embodied in a program or software. The instructions may bestored in a memory location, such as the memory 810. The instructionscan be directed to the CPU 805, which can subsequently program orotherwise configure the CPU 805 to implement methods of the presentdisclosure. Examples of operations performed by the CPU 805 can includefetch, decode, execute, and write back.

The CPU 805 can be part of a circuit, such as an integrated circuit. Oneor more other components of the system 801 can be included in thecircuit. In some cases, the circuit is an application specificintegrated circuit (ASIC).

The storage unit 815 can store files, such as drivers, libraries andsaved programs. The storage unit 815 can store user data, e.g., userpreferences and user programs. The computer system 801 in some cases caninclude one or more additional data storage units that are external tothe computer system 801, such as located on a remote server that is incommunication with the computer system 801 through an intranet or theInternet.

The computer system 801 can communicate with one or more remote computersystems through the network 830. For instance, the computer system 801can communicate with a remote computer system of a user (e.g.,operator). Examples of remote computer systems include personalcomputers (e.g., portable PC), slate or tablet PC's (e.g., Apple® iPad,Samsung® Galaxy Tab), telephones, Smart phones (e.g., Apple® iPhone,Android-enabled device, Blackberry®), or personal digital assistants.The user can access the computer system 801 via the network 830.

Methods as described herein can be implemented by way of machine (e.g.,computer processor) executable code stored on an electronic storagelocation of the computer system 801, such as, for example, on the memory810 or electronic storage unit 815. The machine executable ormachine-readable code can be provided in the form of software. Duringuse, the processor 805 can execute the code. In some cases, the code canbe retrieved from the storage unit 815 and stored on the memory 810 forready access by the processor 805. In some situations, the electronicstorage unit 815 can be precluded, and machine-executable instructionsare stored on memory 810.

The code can be pre-compiled and configured for use with a machine havea processer adapted to execute the code, or can be compiled duringruntime. The code can be supplied in a programming language that can beselected to enable the code to execute in a pre-compiled or as-compiledfashion.

Aspects of the systems and methods provided herein, such as the computersystem 801, can be embodied in programming. Various aspects of thetechnology may be thought of as “products” or “articles of manufacture”typically in the form of machine (or processor) executable code and/orassociated data that is carried on or embodied in a type ofmachine-readable medium. Machine-executable code can be stored on anelectronic storage unit, such memory (e.g., read-only memory,random-access memory, flash memory) or a hard disk. “Storage” type mediacan include any or all of the tangible memory of the computers,processors or the like, or associated modules thereof, such as varioussemiconductor memories, tape drives, disk drives and the like, which mayprovide non-transitory storage at any time for the software programming.All or portions of the software may at times be communicated through theInternet or various other telecommunication networks. Suchcommunications, for example, may enable loading of the software from onecomputer or processor into another, for example, from a managementserver or host computer into the computer platform of an applicationserver. Thus, another type of media that may bear the software elementsincludes optical, electrical and electromagnetic waves, such as usedacross physical interfaces between local devices, through wired andoptical landline networks and over various air-links. The physicalelements that carry such waves, such as wired or wireless links, opticallinks or the like, also may be considered as media bearing the software.As used herein, unless restricted to non-transitory, tangible “storage”media, terms such as computer or machine “readable medium” refer to anymedium that participates in providing instructions to a processor forexecution.

Hence, a machine-readable medium, such as computer-executable code, maytake many forms, including but not limited to, a tangible storagemedium, a carrier wave medium or physical transmission medium.Non-volatile storage media include, for example, optical or magneticdisks, such as any of the storage devices in any computer(s) or thelike, such as may be used to implement the databases, etc. shown in thedrawings. Volatile storage media include dynamic memory, such as mainmemory of such a computer platform. Tangible transmission media includecoaxial cables; wire (e.g., copper wire) and fiber optics, including thewires that comprise a bus within a computer system. Carrier-wavetransmission media may take the form of electric or electromagneticsignals, or acoustic or light waves such as those generated during radiofrequency (RF) and infrared (IR) data communications. Common forms ofcomputer-readable media therefore include for example: a floppy disk, aflexible disk, hard disk, magnetic tape, any other magnetic medium, aCD-ROM, DVD or DVD-ROM, any other optical medium, punch cards papertape, any other physical storage medium with patterns of holes, a RAM, aROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip orcartridge, a carrier wave transporting data or instructions, cables orlinks transporting such a carrier wave, or any other medium from which acomputer may read programming code and/or data. Many of these forms ofcomputer readable media may be involved in carrying one or moresequences of one or more instructions to a processor for execution.

The computer system 801 can include or be in communication with anelectronic display that comprises a user interface (UI) for providing,for example, a model design or graphical representation of a 3D objectto be printed. Examples of UI's include, without limitation, a graphicaluser interface (GUI) and web-based user interface. The computer systemcan monitor and/or control various aspects of the 3D printing system.The control may be manual or programmed. The control may rely onfeedback mechanisms that have been pre-programmed. The feedbackmechanisms may rely on input from sensors (described herein) that areconnected to the control unit (i.e., control system or control mechanisme.g., computer). The computer system may store historical dataconcerning various aspects of the operation of the 3D printing system.The historical data may be retrieved at predetermined times or at awhim. The historical data may be accessed by an operator or by a user.The historical and/or operative data may be displayed on a display unit.The display unit (e.g., monitor) may display various parameters of the3D printing system (as described herein) in real time or in a delayedtime. The display unit may display the current 3D printed object, theordered 3D printed object, or both. The display unit may display theprinting progress of the 3D printed object. The display unit may displayat least one of the total time, time remaining and time expanded onprinting the 3D object. The display unit may display the status ofsensors, their reading and/or time for their calibration or maintenance.The display unit may display the type of powder material used andvarious characteristics of the material such as temperature andflowability of the powder. The display unit may display the amount ofoxygen, water and pressure in the printing chamber (i.e., the chamberwhere the 3D object is being printed). The computer may generate areport comprising various parameters of the 3D printing system atpredetermined time(s), on a request (e.g., from an operator), or at awhim.

Methods and systems of the present disclosure can be implemented by wayof one or more algorithms. An algorithm can be implemented by way ofsoftware upon execution by one or more computer processors.

EXAMPLES

The following are illustrative and non-limiting examples of methods ofthe present disclosure.

Example 1

In a 25 cm by 25 cm by 30 cm container at ambient temperature andpressure, 1.56 kg Stainless Steel 316L powder of average particle size35 μm is deposited in a container accommodating a powder bed. Thecontainer is disposed in an enclosure. The enclosure is purged withArgon gas for 5 min. A layer of an average height of 2 mm was placed inthe container. Two substantially flat surfaces were fabricated with a200 W fiber 1060 μm laser beam using the selected laser melting method.The two substantially flat surfaces were connected to the base viaauxiliary supports to serve as reference points (as shown in FIG. 21A,2103 and 2104). Two additional flat planes were fabricated withoutauxiliary supports using a method described herein (as shown in FIG.21A, 2101 and 2102). The four surfaces were fabricated such that theylay substantially on the same plane. Subsequently, a layer of powdermaterial having an average height of 75 μm was deposited on top of theplanes using a powder dispenser described herein. The powder was leveledto 50 μm using a leveling member described herein. The surfaces weresubsequently revealed using a soft puff of air from a directionsubstantially perpendicular to the exposed surface of the powder bed.Images were collected by a 2 Mega pixel charge-coupled device (CCD)camera and analyzed via image processing program to ascertain the degreeof plane movement. FIGS. 21A-B show examples of the experimentalresults, with FIG. 21A showing the planes before leveling by theleveling member, and FIG. 21B showing the planes after leveling by theleveling member (FIG. 21B shows the two anchored reference planes 2113and 2114, and the two suspended planes 2111 and 2112).

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. It is not intendedthat the invention be limited by the specific examples provided withinthe specification. While the invention has been described with referenceto the aforementioned specification, the descriptions and illustrationsof the embodiments herein are not meant to be construed in a limitingsense. Numerous variations, changes, and substitutions will now occur tothose skilled in the art without departing from the invention.Furthermore, it shall be understood that all aspects of the inventionare not limited to the specific depictions, configurations or relativeproportions set forth herein which depend upon a variety of conditionsand variables. It should be understood that various alternatives to theembodiments of the invention described herein may be employed inpracticing the invention. It is therefore contemplated that theinvention shall also cover any such alternatives, modifications,variations or equivalents. It is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.

What is claimed is:
 1. A method for generating a three-dimensionalobject suspended in a powder bed, comprising: (a) providing the powderbed in an enclosure, wherein the powder bed comprises individualparticles formed of a material selected from the group consisting of anelemental metal, metal alloy, ceramic, and an allotrope of elementalcarbon; (b) transforming at least a portion of the powder bed into atransformed material; and (c) hardening the transformed material to forma hardened material as part of the three-dimensional object, whichthree-dimensional object comprises one or more layers of hardenedmaterial and is suspended in the powder bed during formation, whereinall layers of hardened material have a radius of curvature of at leastabout 5 centimeters up to substantially flat, and wherein the powder bedis devoid of a supporting scaffold substantially enclosing thethree-dimensional object.
 2. The system of claim 1, wherein (c)comprises hardening the transformed material to form a plurality oflayers of hardened material as part of the three-dimensional object,each of which has a radius of curvature of from at least about 5centimeters up to substantially flat.
 3. The method of claim 1, whereinall layers of hardened material have a radius of curvature of at leastabout 10 centimeters up to substantially flat.
 4. The method of claim 1,wherein the one or more layers of hardened material are devoid of atleast two metals that form in (b) a eutectic alloy.
 5. The method ofclaim 1, wherein the one or more layers of hardened material comprise atmost an elemental metal that is of a single elemental metal composition.6. The method of claim 1, wherein the one or more layers of hardenedmaterial comprise a metal alloy that is of a single metal alloycomposition.
 7. The method of claim 1, wherein the one or more layers ofhardened material are of a single material composition.
 8. The method ofclaim 1, wherein a fundamental length scale of the three-dimensionalobject is about 120 micrometers or more.
 9. The method of claim 1,wherein the three-dimensional object is not supported by auxiliarysupport in the powder bed.
 10. The method of claim 1, wherein thethree-dimensional object is devoid of auxiliary support.
 11. The methodof claim 1, wherein the three-dimensional object comprises an auxiliarysupport feature that is suspended in the powder bed.
 12. The method ofclaim 1, wherein the one or more layers of hardened material are devoidof at least a first metal and a second metal that are capable of forminga eutectic metal alloy together.
 13. The method of claim 1, wherein theone or more layers of hardened material are devoid of a metal alloy thatis formed in (b) from at least a first metal and a second metal.
 14. Themethod of claim 1, wherein upon formation of the hardened material, thepowder bed comprises individual particles that are flowable.
 15. Themethod of claim 1, wherein the individual particles are formed of theelemental metal or metal alloy.
 16. The method of claim 1, wherein thepowder bed is provided adjacent to a base that is positioned within theenclosure, and wherein upon formation of the hardened material, thethree-dimensional object is not connected to the base.
 17. A system forgenerating a three-dimensional object suspended in a powder bed,comprising: an enclosure that accommodates the powder bed, wherein thepowder bed comprises individual particles formed of a material selectedfrom the group consisting of an elemental metal, metal alloy, ceramic,and an allotrope of elemental carbon; an energy source that provides anenergy beam to at least a portion of the powder bed; and a controlleroperatively coupled to the energy source and programmed to (i) receiveinstructions to generate at least a portion of the three-dimensionalobject and (ii) direct the energy beam along a predetermined path inaccordance with the instructions to transform the at least a portion ofthe powder bed to a transformed material that hardens to form a hardenedmaterial as part of the three-dimensional object, whichthree-dimensional object comprises one or more layers of hardenedmaterial and is suspended in the powder bed during formation, whereinall layers of hardened material have a radius of curvature of at leastabout 5 centimeters up to substantially flat, and wherein upon formationof the hardened material, the powder bed is devoid of a supportingscaffold substantially enclosing the three-dimensional object.
 18. Thesystem of claim 17, wherein the powder bed is disposed adjacent to abase that is positioned within the enclosure, and wherein upon formationof the hardened material, the three-dimensional object is not connectedto the base.
 19. The system of claim 17, wherein the three-dimensionalobject is devoid of auxiliary support.
 20. The system of claim 17,wherein the one or more layers of hardened material are devoid of atleast two metals that form a eutectic alloy.
 21. The system of claim 17,wherein the energy beam comprises an electromagnetic energy beam or acharged particle beam.
 22. The system of claim 17, further comprising aheat sink for removing heat from the powder bed, wherein the heat sinkis disposed within the enclosure, and wherein upon formation of thehardened material, at least about 30 percent of the heat removal occursfrom the top surface of the powder bed using the heat sink.